CBSE Class 12 Biology Boards 2021 Sample Paper Solved

SECTION A Questions Marks 1. Why does endosperm development precede embryo development?   2. How many meiotic divisions are required to produce 76 seeds in a Guava fruit?    3. How does pollination take place in water hyacinth and water lily?    4. Name the glands that…

CBSE Class 12 Biology Compartment Question Paper Solved 2020 Set B

SECTION A 1. The role of FSH in the process of spermatogenesis in humans is to   (A) stimulate the secretion of certain factors from Sertoli cells.   (B) inhibit the secretion of testosterone from the interstitial cells.   (C) stimulate the action of testosterone on Sertoli…

CBSE Class 12 Biology Compartment Question Paper Solved 2020 Set A

At which trophic level or levels does the species VIII function ?   (A) 2nd and 3rd consumer   (B) 1st consumer   (C) Producer   (D) 3rd and 4th consumer   2. Some cyanobacteria in aquatic and terrestrial environment that enrich the soil by fixing atmospheric nitrogen are    (…

CBSE Class 12 Biology Boards 2020 Question Paper Solved Set E

SECTION – A 1. Which one of the following part of the plant when put into the soil is likely to produce new offspring ?   (a) Part of an internode   (b) A stem cutting with a node   (c) Part of a primary root   (d) A flower    2. In a bacterium when RNA-polymerase binds to the…

CBSE Class 12 Biology Boards 2020 Question Paper Solved Set D

SECTION – A 1. Which one of the following is not found in a female gametophyte of an angiosperm ?   (a) Germ pore   (b) Synergids   (c) Filiform apparatus   (d) Central cell   2. The autosomal disorder/disease in humans is   (a) Colour blindness   (b) Thalassemia   (c)…

CBSE Class 12 Biology Boards 2020 Question Paper Solved Set C

SECTION A Note : Choose the correct option from the choices given in each of the following questions :   1. Introduction of an alien DNA into a plant host cell is achieved by making them   (A) Competent with bivalent ions   (B) Using microinjections   (C) Using gene gun   (D)…

CBSE Class 12 Biology Boards 2020 Question Paper Solved Set B

SECTION A Note : Choose the correct option from the choices given in each of the following questions.   1. Cleistogamous flowers are self-pollinated because   (A) they are bisexual flowers which do not open at all.   (B) they are bisexual and open flowers.   (C) they are…

CBSE Class 12 Biology Boards 2020 Question Paper Solved Set A

SECTION A 1. Meselson and Stahl carried out centrifugation in CsCl2 density gradient to separate : (A) DNA from RNA (B) DNA from protein (C) The normal DNA from 15N-DNA (D) DNA from tRNA   2. Self-pollination is fully ensured if 1 (A) the flower is bisexual. (B) the style is…

CBSE Class 12 Biology Respiration Notes

Breathing & Exchange of Gases Introduction   • It is a process of oxidation of organic compounds in cell in which energy is released.   • According to scientist G.S. Carter, there are 3 steps in respiration :   1.1 External respiration :…

CBSE Class 12 Biology HOTs Organisms And Environment

 Organisms And Environment Q.1.Identify the biome distribution with respect to annual temperature and precipitation from the following graph answer the A, B,C&D. Answer: A – Tropical forest              B - Grassland              C – Desert              D – Arctic and…

CBSE Class 12 Biology HOTs Biodiversity And Conservation

Question. Ex situ strategies include I. zoological parks II. seed/pollen banks III. gene bank and tissue cultures IV. botanical garden Choose the correct option. (a) II, III and IV (b) I, II and III (c) I, II and IV (d) I, II, III and IV Answer: D Question. Which one of the…

CBSE Class 12 Biology HOTs Ecosystem

Question. A bear that eats a fish that further ate bugs that ate lgae is a (a) primary producer (b) primary consumer (c) secondary consumer (d) tertiary consumer Answer : D Question. Fill up the blanks. I. Animals which feed directly on plants, are called …A…. II.…

CBSE Class 12 Biology HOTs Biotechnology Principles and Processes

Question. Why foreign DNA cannot pass through cell membrane? (a) DNA is hydrophobic (b) DNA is hydrophilic (c) DNA is rich in proteins (d) DNA is heavy Answer : B Question. Consider the following statements and select the correct option. (a) A soil inhabiting plant…

CBSE Class 12 Biology HOTs Organism And Population

Question. The attributes of population but not of the individual are (a) birth rate (b) death rate (c) sex ratio (d) All of these Answer : D Question. Select the statement which explains best parasitism. (a) One organism is benefitted (b) Both the organisms are benefitted (c…

CBSE Class 12 Biology HOTs Environmental Issues

Very Short Answer Type Questions Question. What is the raw material for polyblend? Answer : Polyblends are natural man made fibres, made by the mixture of two or more polymers especially plastic waste products Question. Motor vehicles equipped with catalytic to…