CBSE Class 10 Science Biology Heredity and Evolution Assignment

Read and download free pdf of CBSE Class 10 Science Biology Heredity and Evolution Assignment. Get printable school Assignments for Class 10 Science. Standard 10 students should practise questions and answers given here for Chapter 9 Heredity And Evolution Science in Grade 10 which will help them to strengthen their understanding of all important topics. Students should also download free pdf of Printable Worksheets for Class 10 Science prepared as per the latest books and syllabus issued by NCERT, CBSE, KVS and do problems daily to score better marks in tests and examinations

Assignment for Class 10 Science Chapter 9 Heredity And Evolution

Class 10 Science students should refer to the following printable assignment in Pdf for Chapter 9 Heredity And Evolution in standard 10. This test paper with questions and answers for Grade 10 Science will be very useful for exams and help you to score good marks

Chapter 9 Heredity And Evolution Class 10 Science Assignment

Question. In evolutionary terms, we have more in common with :
(a) a chinese school boy
(b) a chimpanzee
(c) a spider
(d) a bacterium

Answer : B

Question. The human species has genetic roots in :
(a) America
(b) Africa
(c) Australia
(d) Antarctica

Answer : B

Question. Which of the following gas was not present in early earth atmosphere ?
(a) Ammonia
(b) Oxygen
(c) Hydrogen sulphide
(d) Methane

Answer : B

Question. A gradual change, over a long period, in a form of life is known as :
(a) erosion
(b) evolution
(c) revolution
(d) evaluation

Answer : B

Question. Scientists believe that all life originated in :
(a) the sea
(b) the soil
(c) the ground
(d) the air

Answer : A

Question. According to scientists, aves have evolved from :
(a) mammals
(b) amphibians
(c) reptiles
(d) arthropods

Answer : C

Question. The theory of evolution of species by natural selection was given by :
(a) Mendel
(b) Darwin
(c) Dalton
(d) Lamarck

Answer : B

Question. The term ‘father of genetics’ is used for the scientist :
(a) Morgan
(b) Mendel
(c) Darwin
(d) Marie Curie

Answer : B

Question. One of the following traits cannot be inherited. This one is :
(a) colour of eyes
(b) colour of skin
(c) size of body
(d) nature of hair

Answer : C

Question. Only one of the following characteristic of the parents can be inherited by their children. This one is :
(a) deep scar on chin
(b) snub nose
(c) technique of swimming
(d) cut nose

Answer : B

Question. The organs which perform different functions but have the same basic structure are known as :
(a) homologous organs
(b) analogous organs
(c) homolytic organs
(d) analytic organs

Answer : A

Question. The organs which perform similar functions but have different basic structure are called :
(a) asymmetric organs
(b) analogous organs
(c) homologous organs
(d) homophonic organs

Answer : B

Question. Wing of an insect and forelimb of a bird are :
(a) analogous organs
(b) analeptic organs
(c) homologous organs
(d) homophobic organs

Answer : A

Question : Name the organ analogous to the wings of birds. 
a. Forelimb of human
b. None of these
c. wings of insect
d. Fore-leg of horse
Answer : C
Explanation: Wings of bird and wings of insect both are analogous as both of them perform the same function of flight while structures and origin are different. Feathers of birds originate from their forelimbs, the wings of insects originate from the inner or outer surface of the insect’s body.
Question : Which of the following is not correct-
a. For every molecule of fat there is a gene
b. For production of every enzyme there is a gene
c. For every protein there is a gene
d. For every hormone there is a gene
Answer : A
Explanation: Hormone and enzymes are proteins and formation of any particular protein is controlled by a particular gene. Hence, all other options are correct.
Question : What are the carriers of factor? 
a. Chromosomes
b. Genes
c. Alleles
d. DNA
Answer : A 
Explanation: The carriers of factor (genes) are chromosomes and transfer hereditary information from one generation to another. 
Question : Human being belongs to the species of 
a. Homo habillis
b. Hominidae
c. Homo sapiens
d. Homo erectus
Answer : C 
Explanation: The billions of human beings living today all belong to one species: Homo sapiens. As in all species, there is variation among individual human beings, from size and shape to skin tone and eye color. But we are much more alike than we are different. 
Question : Haemophilia is more commonly seen in human males than in human females because 
a. This disease is due to an X-linked recessive mutation
b. A greater proportion of girls die in infancy
c. This disease is due to an X-linked dominant
d. This disease is due to a Y-linked recessive mutation
Answer : A
Explanation: Hemophilia is a bleeding disorder that slows down the blood clotting process. People who have hemophilia often have longer bleeding after an injury or surgery.
Hemophilia is inherited in an X-linked recessive pattern. A condition is considered X-linked when gene mutation that causes it is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is enough to cause the condition. Since females have two X chromosomes, a mutation must be present in both copies of the gene to cause the hemophilia. Males are affected by Xlinked recessive disorders much more frequently than females. 
Question. Recessive mutations are expressed
(a) always since it is a mutation
(b) in heterozygous condition
(c) neither in homozygous nor in heterozygous condition
(d) in homozygous condition.

Answer : D

Question. XX-XO type of sex determination and XX-XY type of sex determination are the examples of 
(a) male heterogamety
(b) female heterogamety
(c) male homogamety
(d) both (b) and (c).

Answer : A

Question. A plant bearing purple flowers (RR) was cross pollinated with a plant bearing white flowers (rr). What would be the ratio of the plants bearing white flowers and purple flowers respectively in F2 generation when the F1 progeny were self pollinated? 
(a) 1 : 3
(b) 3 : 1
(c) 1 : 1
(d) 2 : 1

Answer : A

Question. In a dihybrid cross four phenotypes form in the ratio of 9 : 3 : 3 : 1, because of 
(a) dominance of one phenotype in each pair ofcontrasting traits
(b) independent assortment of the genes of contrasting traits
(c) crossing over of genes
(d) mixed effect of dominance and independent assortment.

Answer : B

Question. Some of the dominant traits studied by Mendel were 
(a) round seed shape, green seed colour and axial flower position
(b) terminal flower position, green pod colour and inflated pod shape
(c) violet flower colour, green pod colour and round seed shape
(d) wrinkled seed shape, yellow pod colour and axial flower position.

Answer : C

Question. Why were pea plants more suitable than dogs for Mendel’s experiments ? 
(a) There were no pedigree records of dogs.
(b) Pea plants can be self-fertilised.
(c) All pea plants have only two chromosomes.
(d) Dogs have many genetic traits.

Answer : B

Question. Select the incorrect statement. 
(a) In male grasshoppers, 50% of sperms have no sex chromosome.
(b) Female fruitfly is heterogametic.
(c) Human male produces two types of sperms 50% having X chromosome and 50% having Y chromosomes.
(d) In turtle, sex determination is regulated by environmental factors.

Answer : B

Question. Mendel conducted his famous breeding experiments by working on 
(a) Drosophila
(b) Pisum sativum
(c) Escherichia coli
(d) all of these.

Answer : B

Question. The genotypic ratio in F2 generation of monohybrid cross will be 
(a) 1 : 2 : 1
(b) 3 : 1
(c) 1 : 1
(d) 1 : 2.

Answer : A

Question. The main reason for Mendel’s success in discovering the principles of inheritance was 
(a) he considered each character separately
(b) he was lucky not to encounter with linkage problem
(c) the plant was pure breeding
(d) all of these.

Answer : D

Fill in the following blanks with suitable words :
(a) The human forelimb and bat’s forelimb are an example of ..................... organs whereas an insect’s wing and a bat’s wing are an example of ..................... organs.
(b) The evolution of eye is an example of evolution by .....................
(c) The scientific name of all human beings is .....................
(d) Broccoli has evolved from ..................... by the process of artificial selection.
(e) The theory of natural selection for evolution was proposed by .....................
Answer : (a) homologous ; analogous (b) stages (c) Homo sapiens (d) wild cabbage (e) Darwin


Assertion & Reasoning Based MCQs

(a) Both assertion and reason are true, and reason is correct explanation of the assertion.
(b) Both assertion and reason are true, but reason is not the correct explanation of the assertion.
(c) Assertion is true, but reason is false.
(d) Assertion is false, but reason is true.

Question. Assertion : Test cross is a back cross. 
Reason : In test cross, individual is crossed with recessive parent.

Answer : B

Question. Assertion : The principle of segregation given by Mendel is the principle of purity of gametes. 
Reason : Gametes are pure for a character and do not mix up.

Answer : A

Question. Assertion : In grasshoppers, females are heterogametic and males are homogametic. 
Reason : In grasshoppers, male has only one sex chromosome (XO) whereas the female has sex chromosomes (XX).

Answer : D

Question. Assertion : Pure lines are called true breeds. 
Reason : True breeds are used for cross breeding.

Answer : B

Question. Assertion : If mother is homozygous for black hair and father has red hair then their child can inherit black hair. 
Reason : Gene for black hair is recessive to gene for red hair in humans.

Answer : C

Question. Assertion : A child which has inherited X chromosome from father will develop into a girl child. 
Reason : Girl child inherits X chromosome from father and Y chromosome from mother.

Answer : C

Question. Assertion : In a monohybrid cross, offspring of F1 generation express dominant character. 
Reason : Dominance occurs only in heterozygous state.

Answer : C

Question. Assertion: The traits that are obtained from parents are inherited traits. 
Reason : These traits were developed in the parents during their lifetime.

Answer : C

Question. Assertion : If blood group of both mother and father is ‘O’ then the blood group of children will also be O. 
Reason : Blood group in humans is determined by many alleles of a gene viz. IA, IB, IO.

Answer : B

Question. Assertion : Mendel successfully postulated laws of heredity. 
Reason : He recorded and analysed results of breeding experiments quantitatively.

Answer : A


Very Short Answers

Question : What is gene? Where are genes located? 
Answer :  Gene is a segment of DNA on chromosomes occupying specific position. Genes are located on chromosomes.
Question :  Where will you find the most ancient and recent fossil? 
Answer : The most ancient fossils will occur in the older rocks: whereas most recent fossils willoccur in the youngest rocks.
Question : Name the Father of Genetics. 
Answer : Gregor Johann Mendel  
Question :  How many contrasting traits Mendel noted in garden pea? 
Answer : Seven 

Question. State whether the following statement is true or false : Human beings have evolved from chimpanzees.
Answer : False

Question. Write the names of at least three inorganic molecules which helped in the origin of life on the earth.
Answer : Methane, ammonia and hydrogen sulphide are three inorganic molecules, which helped in the origin of life on the earth.

Question. Name the famous book written by Charles Robert Darwin.
Answer : The Origin of Species

Question. The forelimbs of a frog, a bird and a man show the same basic design (or basic structure) of bones. What name is given to such organs ?
Answer : Homologous organs

Question. Name two organisms which are now extinct and studied from their fossils.
Answer : Trilobites (marine arthropods) and dinosaurs

Question. Out of the wing of a bird, wing of an insect and the wing of a bat :
(a) which two are homologous organs ?
(b) which two are analogous organs ? 
Answer : (a) Wings of bird and wings of bat (b) Wings of birds and wings of insect

Question. State one characteristic which shows that the birds are very closely related to dinosaurs.
Answer : The presence of feathers on birds

Question. Name an animal having rudimentary eyes.
Answer : Planaria has rudimentary eyes.

Question. Name the ancestor of the following : Broccoli, Kohlrabi, Kale
Answer : Wild cabbage

Question. Where did life originate on the earth ?
Answer : the ocean

Question. Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same species ?
Answer : Human beings apart from these variations are said to belong to the same species because humans had descended from a common ancestor and also they have a lot of similarities in their DNA patterns. The variations present in size, colour, and looks are due to the expression of genetic traits at different levels.

Question. Name five varieties of vegetables which have been produced from ‘wild cabbage’ by the process of artificial selection.
Answer : Broccoli, cabbage, cauliflower, kohlrabi and kale are five varieties of vegetables, which have been produced from 'wild cabbage' by the process of artificial selection.

Question. Choose the one term from the following which includes the other three : broccoli, wild cabbage, cauliflower, cabbage
Answer : Wild cabbage

Question. What name is given to the sequence of gradual changes over millions of years in which new species are produced ?
Answer : Evolution

Question. Name the scientist who gave the theory of evolution.
Answer : Charles Darwin

Question : Why are human beings who look so different from each other in terms of size, color and looks said to belong to the same species?
Answer : Human beings belong to same species because of the following reasons:
(a) They have same number of chromosomes.
(b) They have a common ancestor.
(c) They interbreed to produce fertile off springs

Question : What factors could lead to the rise of a new species?
Answer : (a) Natural selection
(b) Genetic drift
(c) Geographical isolation.

Question : Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not?
Answer : In case of an asexually reproducing organism, geographical isolation cannot be a major factor in speciation. This is because in asexual reproduction, only one parent is involved and natural barrier cannot pose a problem.

Question : How does the creation of variations in a species promote survival?
Answer : Variations enable a species to adapt according to the changes and new needs and thus promote survival of species.

Question : A study found that children with light-colored eyes are likely to have parents with lightcolored eyes. On this basis, can we say anything about whether the light eye color trait is dominant or recessive? Why or why not?
Answer : For considering an attribute as dominant or recessive, we'd like knowledge of a minimum of 3 generations. Therefore, it cannot be concluded whether light eye colour is dominant or recessive.

Question : Explain how sexual reproduction gives rise to more viable variations than asexual reproduction. How does this affect the evolution of those organisms that reproduce sexually?
Answer : In sexual reproduction, the DNA comes from two parents. Therefore, the variations are more
obvious. When the next generation reproduces, it passes on the characteristics inherited from the parents as well
as its own individual traits. This results in similarities and variations. So, due to more variations, evolution in
sexually reproducing organisms proceed at a quicker pace than in asexually reproducing organisms.


Short Answers

Question : What is natural selection in modern terms? Elucidate the three different effects of natural selection on variation. 
Answer :  Natural selection: In modern term natural selection is differential reproduction.
Natural selection is main evolutionary process which causes the change of allele frequencies or in other words selection is the consistent differences in contribution of various genotypes to the next generation.
If in a population both small and largest individuals contribute relatively fewer offspring to the next generation then those closer to the average size do, stabilizing selection is operating.
If centre of population contributes more then equilibrium is maintained while if extremes of population work then two peaks in the distribution of a trait produced, while former is disruptive selection.
Question : What is speciation? List four factors that could lead to speciation. Which of these cannot be a major factor in the speciation of a self-pollinating plant species? Give reason to justify your answer. 
Answer :  Speciation is the process by which new species develop from the existing species.
Factors responsible for speciation are as follows
i. Genetic drift
ii. Mutation
iii. Natural selection
iv. Migration
Out of the following, geographical isolation will not be a major factor in the speciation of a self-pollinating plant species. Because, here single parent is involved as male and female gametes both are contributed by same individual. Hence, even though if a selfpollinating plant is seperated geographically they can reproduce without creating much variation. 
Question : In evolutionary terms can we say that which among bacteria, spider, fish and chimpanzee has a 'better' body design? Why or why not? 
Answer : It depends on our perception of ‘better’ design. If complexity of body design is the criterion, then chimpanzee is obviously better than bacteria. But if ability of survival in almost all kinds of habitat is a criterion then bacteria are far ahead than any other group of organisms.
Question : Give difference between diploid and haploid.
Answer : 

Long Answers

Question. (a) What is meant by ‘heredity’ ? What are the units of heredity.
(b) State Mendel’s first law of inheritance.
Answer : (a) The transmission of characters from parents to the offspring's is called heredity. The units of heredity are genes. (b) According to Mendel's first law of inheritance: The characteristics (or traits) of an organism are determined by internal 'factors' which occur in pairs.

Question. (a) Why did Mendel choose pea plants for conducting his experiments on inheritance ?
(b) State Mendel’s second law of inheritance.
Answer : (a) Mendel selected garden pea plant for his experiments because of the following characteristics:
(i) The flowers of this plant are bisexual.
(ii) They are self-pollinating, and thus, self and cross pollination can easily be performed.
(iii) The different physical characteristics were easy to recognise and study.
(iv) They have a shorter life span and are the plants are easier to maintain.
(b) According to Mendel's law of independent assortment, during the inheritance of two or more characters, the assortment of individual traits takes place independently during gamete formation. Thus each allele of a pair segregates independently and each gamete formed contains one allele of that trait. This law is inapplicable for linked genes. 

Question. (a) What do you understand by the term ‘variation’ ?
(b) Name two human traits which show variation.
(c) How does the creation of variation in a species ensure its survival ?
Answer : (a) The differences in the characters (or traits) among the individuals of a species is called variation.
(b) Human height and skin colour are two traits which show variation.
(c) The great advantage of variation to a species is that it increases their chances of survival in a changing environment.

Question. (a) What are genes ? Where are they located in our body ?
(b) What is meant by dominant genes and recessive genes ? Give one example of each.
(c) Explain how, characteristics (or traits) are inherited through genes.
Answer : (a) Genes are the units of heredity which transfer characteristic from parents to their offspring’s during reproduction. Genes are located on the chromosomes inside the nucleus of our cells in the body. .
(b) The gene which decides the appearance of an organism even in the presence of an alternative gene is known as dominant gene. The gene which can decide the appearance of an organism only in the presence of another identical gene is called a recessive gene. The dominant gene is represented by a capital letter and the corresponding recessive gene is represented by the corresponding small letter. For example, in pea plants, the dominant gene for tallness is T and the recessive gene for dwarfness is t.
(c) There are a pair of genes for each characteristic of an organism, while one is dominant gene and the other is recessive gene. Each parent passes only one of the two genes of the pair for each characteristic to its progeny through gametes. Thus, the male gamete and the female gamete carry one gene for each characteristic from the gene pairs of the parents. When a male gamete fuses with a female gamete during fertilisation they make a new cell called zygote which grows and develops to form a new organism having characteristics from both the parents which it has inherited through genes.

Question. (a) How do Mendel’s experiments show that traits may be dominant or recessive ?
(b) How do Mendel’s experiments show that traits are inherited independently ?
Answer : (a)Mendel selected true breeding tall (TT) and dwarf (tt) pea plants. When a tall pea plant is crossed with a short (dwarf) pea plant, all the F1 hybrids are tall. (i.e., in this case, the gene causing tallness is dominant while the gene causing dwarfness is recessive.).The trait expressing itself in the hybrid is the dominant one. Mendel’s first law of inheritance states that when a pair of contrasting factors is brought in a hybrid, one factor inhibits the appearance of the other. The one which inhibits is the dominant one and which is inhibited is recessive.
(b)Mendel performed an experiments in which he took a tall plant with round seeds and a short plant with wrinkled-seeds. In F1, They were all tall and had round seeds. Tallness and round seeds were thus dominant traits. When, he used these F1 progeny to generate F2 progeny by self-pollination, he found that some F2 progeny were tall plants with round seeds, and some were short plants with wrinkled seeds. At the same time there tall plants, but had wrinkled seeds, while others were short, but had round seeds. Thus, Mendel’s experiments show that the tall/short trait and the round seed/wrinkled seed trait are independently inherited.

Question. Pure-bred pea plants A are crossed with pure-bred pea plants B. It is found that the plants which look like A do not appear in F1 generation but re-emerge in F2 generation. Which of the plants A and B are : (i) tall, and (ii) dwarf ? Give reason for your answer.
Answer : (i) B (ii) A ; Dwarf pea plants do not appear in F1 generation

Question. Pure-bred tall pea plants are first crossed with pure-bred dwarf pea plants. The pea plants obtained in F1 generation are then cross-bred to produce F2 generation of pea plants.
(a) What do the plants of F1 generation look like ?
(b) What is the ratio of tall plants to dwarf plants in F2 generation ?
(c) Which type of plants were missing in F1 generation but reappeared in F2 generation ?
Answer : (a) All tall plants (b) 3 : 1 (c) Dwarf plants

Question. A plant has two varieties, one with red petals and the other with white petals. When these two varieties are cross-pollinated, all the offsprings have red petals ?
(a) Which gene is dominant ?
(b) Choose suitable letters to represent the two genes.
Answer : (a) Red colour (b) Rr

Question. A red-haired woman marries a brown-haired man, and all the children are brown haired. Explain this genetically.
Answer : The brown hair colour genes are dominant to the red hair colour genes ; The genotype of brown hair can be represented as BB and that of red hair as bb

Question. A black mouse mates with a brown mouse, and all the offsprings are black.
(a) Why are no brown offsprings produced ?
(b) If two of the black offpsrings mate with each other what kind of offspring would you expect and in what proportions ? Give reason for your answer.
Answer : (a) Because black colour genes are dominant over brown colour genes (b) Three black mice and one brown mouse will be obtained in F2 generation ; It is a monohybrid cross

Question. (a) E is the gene for brown eye colour and and e is the gene for blue eye colour. Which gene is (i) recessive, and (ii) dominant ?
(b) Both father and mother have the genes Ee in their cells. What colour are their eyes ?
(c) Which combination of genes in the zygote will produce children with blue eyes ?
(d) Which combinations of genes in the zygote will produce children with brown eyes ?
Answer : (a) (i) e (blue colour) (ii) E (brown colour) (b) Brown eyes (c) ee (d) EE and Ee

Question. What are the possible blood groups likely to be inherited by children born to a group A mother and a group B father ? Explain your reasoning.
Answer : Possible genotypes are IA IB, IA IO, IB IO and IO IO. So, the possible phenotypes or blood groups are : AB, A, B and O

Question. A couple with a newborn baby is troubled that the child does not resemble either of them. Suspecting that a mixup occurred at the hospital, they check the blood type of the infant. It is type O. Because the father is type A and the mother type B, they conclude that a mixup has definitely occurred. Are they correct ? Give reason for your answer.
Answer : No, the parents are not correct. The baby born to father having blood groups A and mother having blood group B can have any one of the four possible blood groups : A, B , AB and O.

Question. A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits—blood group A or O — is dominant ? Why or why not ?
Answer : No (Case I : If father’s blood group A is dominant trait, his genotypes will be IAIA and IAIO; and mother’s blood group O being recessive trait, her genotype will be IOIO.
So, daughter can receive one recessive allele IO from father and another recessive allele IO from mother to have genotype IOIO and hence blood group O. Case II : If father’s blood group A is recessive trait, his genotype will be IAIA; and mother’s blood group O being dominant trait, her genotypes will be IOIO and IOIA. In this case, daughter can receive a dominant allele IO from mother and a recessive allele IA from father to have genotype IOIA and hence blood group O).

Question. A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggested that the genetic make up (or genotype ) of the tall parent can be depicted as :
(a) TTWW (b) TTww (c) TtWW (d) TtWw
Give reason for your choice.
Answer : (c) TtWW (Hint. T is the gene form for tallness, t for dwarfness, W for violet colour and w for white colour. T and W are dominant genes whereas t and w are recessive genes)

Question. A person first crossed pure-bred pea plants having round-yellow seeds with pure-bred pea plants having wrinkled-green seeds and found that only A-B type of seeds were produced in the F1 generation. When F1 generation pea plants having A-B type of seeds were cross-bred by self-pollination, then in addition to the original round-yellow and wrinkled-green seeds, two new varieties A-D and C-B type of seeds were also obtained.
(a) What are A-B type of seeds ?
(b) State whether A and B are dominant traits or recessive traits.
(c) What are A-D type of seeds ?
(d) What are C-B type of seeds ?
(e) Out of A-B and A-D types of seeds, which one will be produced in (i) minimum numbers, and
(ii) maximum numbers, in the F2 generation ?
Answer : (a) Round yellow (b) A (round) and B (yellow) are dominant traits (c) Round-green (d) Wrinkled-yellow (e) (i) A–D (ii) A–B

Question. The person A has only B chromosomes in all its gametes. On the other hand, another person C has chromosome D in half of gametes and chromosome E in the other half of gametes. When chromosomes B and D combine during fertilisation, a female zygote results. On the other hand, combination of B and E chromosomes produces a male zygote.
(a) What are chromosomes (i) B (ii) D, and (iii) E ?
(b) Out of B, D and E, which two chromosomes are of the same type ?
(c) Which chromosome is smaller in size ?
(d) What is the general name of chromosomes such as B and E ?
(e) Out of the two persons A and C, which one is (i) male, and (ii) female ?
Answer : (a) (i) X chromosomes (ii) X chromosome (iii) Y chromosome (b) B and D (both are X chromosomes) (c) E (d) Sex chromosomes (e) (i) C (ii) A

Question. Mendel first crossed pure-bred pea plants having round-yellow seeds with pure-bred pea plants having wrinkled-green seeds and found that only round-yellow seeds were produced in the F1 generation. When F1 generation pea plants having round-yellow seeds were cross-bred by self pollination, then peas having roundyellow seeds, round green seeds, wrinkled-yellow seeds and wrinkled-green seeds were produced. Mendel collected a total of 2160 seeds.
(a) What will be the number of (i) round green seeds (ii) wrinkled green seeds (iii) round yellow seeds, and (iv) wrinkled-yellow seeds ?
(b) Which ‘ratio’ as established by Mendel have you made use of in answering the part (a) above ?
Answer : (a) (i) 405 (ii) 135 (iii) 1215 (iv) 405 (b) Dihybrid ratio

Question. Pure-bred round-yellow pea seeds have genotype RRYY and the pure-bred wrinkled-green pea seeds have genotype rryy. Keeping this in mind, write the phenotypes of the following genotypes of hybrid pea seeds :
(a) Rryy (b) rrYy (c) rrYY (d) RrYy (e) RRyy
Answer : (a) Round-green (b) Wrinkled-yellow (c) Wrinkled-yellow (d) Round-yellow (e) Round-green

Question : Bacteria have a simpler body plan when compared with human beings. Does it mean that human beings are more evolved than bacteria? Provide a suitable explanation.
Answer :  It depends on our perspective through which we try to evaluate evolution. If complexity in body design is the parameter to define evolution, then human beings are more evolved than bacteria. Human beings are multicellular with organ system level of organisation whereas bacteria is unicellular and show cellular level of organization. In terms of complexity human beings are definitely highly evolved compared to bacteria.
But when we compare the ability of survival, then situation is just opposite. Human beings are living in almost every part of the earth, but they can live only on land Moreover, in extreme environmental conditions, human beings make artificial facilities to counter the adverse conditions. This means their body is not adapted to withstand extreme climatic conditions they have to thrive on artificially created resources. Bacteria, on the other hand, are known to be present almost everywhere on earth. They are known to live even in some of the harshest conditions; like Sulphur spring, crater of volcano, etc. Bacteria can survive in highly acidic environment and they can survive extreme temperatures. From this angle, bacteria can be considered as more evolved than human beings.
Question : Name any five vegetables generated from a common ancestor through artificial selection rather than natural selection. Also mention the features for which each vegetable is selected? 
Answer :  Humans have, for more than two thousand years, cultivated wild cabbage. They have selected various character artificially rather than selecting naturally, which led to development of various species. It has resulted in generation of the following vegetables due to some specific characters such as:
i. Cabbage selected for short distance between leaves.
ii. Broccoli selected for arrested flower development and thick stem.
iii. Cauliflower selected for sterile flowers forming a large flower.
iv. Kohlrabi selected for a swollen edible stem.
v. Kale selected for large leaves.

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