Frank Brothers Solutions for ICSE Class 9 Biology Chapter 4 Tissues

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Question 1:
Answer: Permanent tissue is a group of cells which temporarily or permanently cease to divide and thus assume permanent form and function. Permanent tissues are of three types – simple tissues, complex tissues and special tissues.
These cells are specialized for specific jobs like protection or support rather than growing. Once they reach this stage, they rarely go back to dividing and remain in a fixed state for their entire life.
Teacher's Tip: Think of permanent tissues as the "graduated" cells that have finished school (dividing) and started a career (specialized job).
Exam Tip: Name all three types of permanent tissues to score full marks in classification questions.

Question 2:
Answer: Sclerenchyma is a type of simple tissue present commonly in roots, stems, leaves and petioles. Its cells are dead, elongated and narrow with thickened and lignified cell walls. Sclerenchyma is of two types i.e. fibres and sclerids. Sclerenchyma gives strength, rigidity and flexibility to the plant body, thus enabling it to withstand various strains.
These cells have very thick walls filled with a glue-like substance called lignin which makes them incredibly tough. This tissue is the reason why coconut shells and walnut husks are so hard to break.
Teacher's Tip: Sclerenchyma is like the "armor" or "bones" of a plant.
Exam Tip: Mention the presence of "lignified cell walls" to earn high marks when describing this tissue.

Question 3:
Answer: Xylem is a complex plant tissue composed of several types of cells which are:
1. Tracheids – These cells are long and tubular with thick, rigid and lignified walls and pointed ends. Tracheids are present in all vascular plants. These conduct water and minerals from root to stem.
2. Vessels – These are long cylindrical cells with lignified walls, placed one above the other to form a pipe like structure. They participate in the conduction of water and minerals.
3. Xylem fibres – These are sclerenchymatous fibres found attached to xylem. These provide strength to the plant organs.
4. Xylem parenchyma – This is the living component of xylem. Xylem parenchyma is composed of simple parenchyma cells found in xylem. These are connected with tracheids or vessels through simple or bordered pits. Their function is to store food material.
Xylem acts as the plant's plumbing system, moving water and minerals from the roots all the way to the leaves. Except for the parenchyma, most of these cells are dead at maturity to allow for easier water flow through their hollow tubes.
Teacher's Tip: Xylem = "Xy-to-the-Sky" (it moves water up).
Exam Tip: Identify Xylem Parenchyma as the only "living" component to demonstrate deep understanding of the tissue structure.

Question 4:
Answer: Phloem is a complex plant tissue found in all parts of the plant like roots, stems and leaves and is mainly responsible for the conduction of organic food prepared by the plant. Phloem is made up of four components which are:
1. Sieve tubes
2. Companion cells
3. Phloem parenchyma
4. Phloem fibres
While xylem moves water up, phloem carries the food made in leaves to every other part of the plant. This bidirectional movement ensures that even the roots underground get the energy they need to grow.
Teacher's Tip: Phloem sounds like "Flow-em" (it moves food).
Exam Tip: List all four components correctly to get full marks for the structure of phloem.

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Question 5:
Answer: 1. Tissue is a group of cells of similar structure and function.
2. Vascular tissue is the complex plant tissue in higher plants that is composed of xylem and phloem and is concerned with conducting water, minerals and organic food throughout the plant body.
3. Meristematic tissue is a group of cells which constantly divide and produce cells indefinitely throughout the life of the plant.
4. Permanent tissue refers to a group of cells which temporarily or permanently cease to divide and thus assume permanent form and function.
Tissues are the building blocks that make up larger organs like the heart in animals or leaves in plants. Understanding these groups helps us see how complex life is organized from many tiny individual cells.
Teacher's Tip: Remember the hierarchy: Cells $\rightarrow$ Tissues $\rightarrow$ Organs $\rightarrow$ Organ Systems.
Exam Tip: Always mention that meristematic tissues are "dividing" while permanent tissues are "non-dividing" to highlight the main difference.

Question 6:
Answer: (i) Cell: Cell is the smallest basic structural and functional unit of all living organisms. It is present in all living organisms.
Tissue: Tissue is a group of cells of similar structure and function. It is absent in unicellular organisms.
(ii) Parenchyma: It is concerned with photosynthesis, storage of various materials and wound healing. Parenchyma cells have thin cell walls.
Collenchyma: It provides mechanical support and elasticity to the plant body. The cell wall of collenchyma cell is unevenly thickened.
(iii) Organ: It is macroscopic. Several tissues coordinate together to form an organ. Example - Heart, lung, brain, kidney.
Organelle: It is microscopic. There are many organelles present within a cell. Example - Mitochondria, plastid, $ER$, Golgi apparatus.
(iv) Collenchyma: Collenchyma cells are living. Its cell walls show uneven thickening. Collenchyma provides mechanical support and elasticity to the plant body. Collenchyma may carry out photosynthesis if chloroplast is present. Sclerenchyma: Sclerenchyma cells are dead. Cell walls show uniform thickening. Sclerenchyma gives strength and rigidity to the plant body. Sclerenchyma never carries out the function of photosynthesis.
(v) Nervous tissue: Several neurons group together to form nervous tissue. Nerve tissue transmits signals or impulses within the body.
Nervous system: Nervous system is formed by the coordination of organs like brain and spinal cord as well as nerves. Nervous system makes the organism respond suitably to its environment.
(vi) Blood: It is red in colour. RBCs and WBCs are present. Blood transports respiratory gases, food, hormones etc. throughout the body.
Lymph: It is a colourless fluid. RBCs are absent, whereas WBCs are found in abundance. Lymph protects body against infection.
(vii) Bone: It is a hard and rigid tissue. It is porous. It has a good supply of blood vessels and nerves. It is the main skeletal tissue of the body. It gives shape, support and protection to the body.
Cartilage: It is a flexible tissue. It is non-porous. It has no blood vessels or nerves. It is found only in certain parts of the body like nose, ear, bronchial tubes, rings of trachea, between vertebrae and at the end of long bones. It provides flexibility and support to the body parts.
(viii) Tendon: Tendons connect muscles to bones.
Ligament: Ligaments connect two bones at joints.
These comparisons highlight how different biological structures are adapted for specific functions. For example, bone provides a hard frame for our body while cartilage provides flexible padding at our joints.
Teacher's Tip: For Tendon vs Ligament, remember: "BLB" (Bone to Bone = Ligament) and "MTB" (Muscle to Bone = Tendon).
Exam Tip: Use a T-chart format in your exams for comparison questions to clearly present the differences to the examiner.

Question 7:
Answer: (i) Sclerenchyma Structure: Cells of sclerenchyma are dead. These cells are elongated, narrow, pointed at both ends, thick walled and lignified. Their cell walls are thick due to secondary deposition of lignin. Function: Sclerenchyma gives strength, rigidity and flexibility to the plant body, thereby enabling it to withstand various strains.
(ii) Collenchyma Structure: It is a mechanical tissue consisting of living cells with usually no intercellular spaces. The cell wall is unevenly thickened and the walls are rich in hemicelluloses.
Function: Collenchyma provides mechanical support and elasticity to the plant body. Collenchyma may carry out photosynthesis if chloroplast is present.
(iii) Bone Structure: It is a hard, inflexible and porous skeletal tissue well supplied with blood vessels and nerves. The bone matrix has a rigid mass of inorganic salts of calcium and magnesium. The bone cells called osteocytes are arranged in the form of thin circular layers around a central canal. Osteocytes are present in small spaces connected to one another by a system of canals.
Function: Bone gives shape, support and protection to the body parts.
(iv) Crystal Structure: Three common types of crystals are found in plants: druses (spherical crystal aggregates), raphides (long pointed needles found in bundles), and prisms. Despite the variety of crystal structures found throughout the plant cells, all crystals contain calcium oxalate.
Function: Crystals either protect plants from animals or they may provide extra support.
(v) Phloem Structure: Phloem is a complex plant tissue found in all parts of the plant like roots, stems and leaves. It is made up of four components which are: (a) Sieve tubes, (b) Companion cells, (c) Phloem parenchyma, (d) Phloem fibres.
Function: Phloem carries out the conduction of organic food prepared by the plant.
Each tissue type has a unique microscopic appearance that tells us about its function. For instance, the uneven thickness in collenchyma cells allows growing plants to bend in the wind without snapping or breaking.
Teacher's Tip: Visualizing the structure of bone as a circular "central canal" surrounded by rings helps in remembering its complex anatomy.
Exam Tip: When describing tissues, always mention both the structure (how it looks) and the function (what it does) to provide a complete answer.

Question 8:
Answer: There are two main types of epithelial tissues. These are: (a) Simple and (b) Compound. Simple epithelial tissue is further divided into six sub-groups which are: Columnar epithelium, Ciliated epithelium, Cuboidal epithelium, Squamous epithelium, Glandular epithelium, Sensory epithelium. Compound epithelial tissue is of two types: 1. Stratified epithelium, 2. Transitional epithelium. Functions of epithelial tissue are:
1. It forms a protective layer over the body and protects the underlying cells from drying up, injury, germs and harmful chemicals.
2. It absorbs water and other nutrients inside the body.
3. Some of these cells secrete ear wax, mucus, milk and digestive juices.
Epithelial tissue covers the entire outside of your body as skin and also lines the inside of all your organs. It acts as a smart barrier that keeps germs out while allowing helpful nutrients to pass through.
Teacher's Tip: Epithelium is like the "wrapping paper" of the body.
Exam Tip: List "protection" as the primary function of epithelial tissue for guaranteed marks in function-based questions.

Question 9:
Answer: Nerve cell or neuron is a cell of the nervous system, capable of transmitting signals or impulses within the body. Each neuron consists of a cell body or cyton with a nucleus and elongated hair like extensions called axons and dendrites. Nervous tissue is found in brain, spinal cord and nerves and carries out transmission of signals or impulses within the body.
Neurons are the longest cells in the human body, acting like thin electrical wires to carry messages. They allow your brain to tell your muscles to move almost instantly when you think about it.
Teacher's Tip: Think of the Cyton as the "headquarters" and the Axon as the "delivery cable" for signals.
Exam Tip: Label the three main parts—Cyton, Axon, and Dendrites—carefully if you are asked to draw a neuron diagram.

Question 10:
Answer: Blood is called a tissue since it contains many blood cells i.e. RBCs, WBCs and platelets working together to perform a common function. Blood connects the body systems together bringing the needed oxygen, nutrients, hormones and other signaling molecules, and removing the wastes.
Blood is unique because it is a "fluid" tissue that circulates throughout your entire body. It also plays a vital role in immunity by using white blood cells to fight off harmful infections.
Teacher's Tip: Blood is the body's internal "postal service" delivering oxygen and nutrients where they are needed.
Exam Tip: Classify blood as a "Fluid Connective Tissue" to show scientific accuracy in your classification answers.

Question 11:
Answer: (i) Epithelial tissue: Structure: The cells of epithelium are compactly placed, tightly held together and form a continuous sheet. Epithelial cells are supported below on a basement membrane. These cells may be of different shapes and sizes. Types: There are two main types of epithelial tissues which are: (a) Simple and (b) Compound. Functions: (i) It forms a protective layer over the body and protects the underlying cells from drying up, injury, germs and harmful chemicals. (ii) It absorbs water and other nutrients inside the body. (iii) Some of these cells secrete ear wax, mucus, milk and digestive juices.
(ii) Muscular tissue: Structure – Muscle tissue consists of cells which are elongated and large-sized, hence they are also called muscle fibres. These fibres are of various sizes. Contractile proteins are present in the muscle cells which bring about their contraction and relaxation. The cytoplasm of muscle fibre is called sarcoplasm and is bounded by a membrane called sarcolemma. Types: Muscle tissue is of three types: 1. Striated muscle tissue, 2. Unstriated muscle tissue, 3. Cardiac muscle tissue. Functions – 1. Muscles bring about all voluntary movements done by a person. 2. All the involuntary movements needed to keep the body alive are possible due to muscles.
3. Connective tissue: Structure – This tissue has homogenous matrix which forms its main bulk. The connective tissue cells are living, separated from each other and are few in number. The matrix varies in size and shape and may be solid, gel like or liquid. The nature of the matrix decides the function of the connective tissue. Types – The following are the different types of connective tissue: (a) Loose areolar connective tissue, (b) Fibrous connective tissue, (c) Cartilage connective tissue, (d) Bone, (e) Fluid connective tissue. Functions – (i) Connective tissue connects and binds various organs of our body. (ii) It gives support to the body and forms the skeleton to provide a definite shape. (iii) It transports nutrients, hormones, oxygen and waste material within the body.
(iv) Nervous tissue: Structure – The cells of nervous tissue is called neuron. It is capable of transmitting signals or impulses within the body. Each neuron consists of a cell body or cyton with a nucleus and elongated hair like extensions called axons and dendrites. Axons bundle together to form the nerve. Functions – Nervous tissue is found in brain, spinal cord and nerves. It carries out transmission of signals or impulses within the body.
Muscular tissue is what allows us to move and keep our heart beating, while connective tissue literally holds our entire body together. Each of these four groups is essential for the body to function properly as a whole system.
Teacher's Tip: Muscle fibers are like rubber bands that can contract and relax to create movement in your arms and legs.
Exam Tip: Always distinguish between striated (voluntary) and unstriated (involuntary) muscles to show you understand how movement is controlled.

Question 12:
Answer: (a) – (v)
(b) – (i)
(c) – (iv)
(d) – (ii)
(e) – (vi)
(f) – (iii)
This matching exercise connects specific biological terms to their correct descriptions or functions. Understanding these relationships is the first step toward mastering the vocabulary of the tissue chapter.
Teacher's Tip: Use a ruler to make your matching lines neat, or better yet, write the corresponding letter next to the number.
Exam Tip: Double-check each pair before finalizing your answer in a matching question to avoid simple mix-ups.

Question 13:
Answer: 1. Nervous tissue
2. Cardiac muscle tissue
3. Adipose tissue
4. Xylem
5. Phloem
These tissues represent highly specialized groups of cells found in both plants and animals. For example, adipose tissue is where our body stores fat for energy and insulation.
Teacher's Tip: Remember that xylem and phloem are specific to plants, while nervous and cardiac tissues are specific to animals.
Exam Tip: Be sure to use the full name of the tissue (like "Cardiac muscle tissue" instead of just "Cardiac") for technical accuracy.

Question 14:
Answer: The three kinds of muscles found in human body are:
1. Striated muscle – An example is leg muscle
2. Unstriated muscle – An example is muscles in walls of uterus
3. Cardiac muscle – An example is heart muscle
Striated muscles are the ones you can control to run or jump, whereas unstriated and cardiac muscles work automatically. Your heart (cardiac muscle) never gets tired and keeps pumping for your whole life.
Teacher's Tip: "Striated" means having stripes, which you can see under a microscope!
Exam Tip: Pair each muscle type with its correct example (e.g., Striated with biceps) to ensure full credit.

Question 15:
Answer: 1. Tissue
2. Unicellular organism
3. Organ
These terms define the scale at which we look at biological life. A tissue is larger than a single cell, and an organ is a collection of different tissues working as a unit.
Teacher's Tip: Think of a single brick (cell), a wall (tissue), and a whole room (organ).
Exam Tip: Define a tissue as a "group of similar cells" to provide a scientifically precise definition.

Question 16:
Answer: 1. Stratified epithelial tissue
2. Apical meristem
3. Ligament
4. Ciliated epithelium
5. Cuboidal epithelium
These names belong to specific tissue sub-types with very specialized structures. For instance, ciliated epithelium has tiny hair-like parts that help move mucus in your windpipe.
Teacher's Tip: "Apical" always refers to the tips or points of something, like the root or stem tip.
Exam Tip: Practice the spelling of these technical terms as they are very common in "name the following" questions.

Question 17:
Answer: [Textbook provides a classification chart of plant tissues showing Meristematic (Apical, Lateral, Intercalary) and Permanent (Simple - Parenchyma, Collenchyma, Sclerenchyma and Complex - Xylem, Phloem)].
This chart shows how all plant tissues are related and how they develop from simple dividing cells into complex plumbing and support structures. It provides a visual map of the entire plant tissue system.
Teacher's Tip: Try drawing this chart from memory to quickly master the entire chapter's organization.
Exam Tip: Being able to reproduce this flow chart is a great way to answer long "Classification of Plant Tissue" questions.

Question 18:
Answer: In man, cartilage is found in nose, ear, bronchial tubes, rings of trachea, between vertebrae and at the end of long bones such as ribs. It differs from bone in following ways: Cartilage: It is a flexible tissue. It is non-porous. It has no blood vessels or nerves. It is found only in certain parts of the body like nose, ear, bronchial tubes, rings of trachea, between vertebrae and at the end of long bones. It provides flexibility and support to the body parts. Bone: It is a hard and rigid tissue. It is porous. It has a good supply of blood vessels and nerves. It is the main skeletal tissue of the body and is present throughout the body. It gives shape, support and protection to the body.
While bones provide the strong framework for our body, cartilage provides the "bouncy" or flexible parts that don't snap. You can feel your own cartilage by gently wiggling the tip of your nose or the top of your ear.
Teacher's Tip: Bones are the "bricks" and cartilage is the "rubber padding" at the joints.
Exam Tip: Mention "porosity" and "flexibility" as the two most important differences between bone and cartilage.

Question 19:
Answer: 1. False
2. True
3. False
4. True
5. True
6. True
These True/False answers help clarify common misconceptions about tissue functions and locations. For example, it confirms that some tissues are found throughout the body while others are very localized.
Teacher's Tip: Read True/False statements very carefully, as one small word like "always" or "only" can change the entire meaning.
Exam Tip: In True/False questions, if a statement is false, try to mentally correct it to reinforce your learning.

Question 20:
Answer: 1. (b) sclerenchyma
2. (c) tissue
3. (d) tracheid
4. (b) thin walled and living
5. (d) dicot stems
6. (b) phloem
7. (a) blood devoid of RBCs
8. (a) one bone to another
9. (d) striated and involuntary (referring to cardiac muscle)
10. (a) vascular connective tissue
These multiple-choice answers confirm the specific structural details of both plant and animal tissues. For instance, knowing that ligaments connect "bone to bone" is a fundamental fact in human anatomy.
Teacher's Tip: In MCQs, use the process of elimination to remove the obviously wrong answers first.
Exam Tip: Pay special attention to "Striated and Involuntary"—this is a unique combination that only describes Cardiac muscle.