Looking for the Class 9 Science Chapter 3 Question Answer – Tissues in Action? At SchoolLearners, you’ll find easy-to-understand, NCERT-based solutions that help students prepare for school exams and strengthen their concepts.
Tissues in Action Class 9 Questions and Answers (Exercise)
Revise, Reflect, Refine (NCERT Textbook Page No. 44)
Question 1.
Meristematic tissues divide repeatedly. What property of their cells allows them to do this?
(i) They have thick walls for protection.
(ii) They contain large vacuoles that store nutrients.
(iii) They have thin walls, dense cytoplasm, and large, prominent nucleus.
(iv) They are functionally differentiated cells.
Answer:
(iii) They have thin walls, dense cytoplasm, and large, prominent nucleus.
Question 2.
If a plant is unable to transport food from leaves to roots, which tissue is malfunctioning?
(i) Xylem
(ii) Phloem
(iii) Epidermis
(iv) Sclerenchyma
Answer:
(ii) Phloem
Question 3.
Why are the epithelial tissues that line an animal’s internal organs usually only one or a few cells thick?
(i) To store food efficiently.
(ii) To provide maximum strength.
(iii) To allow quick exchange of materials across them.
(iv) To reduce friction.
Answer:
(iii) To allow quick exchange of materials across them.
Question 4.
You can perform these two jumps (Fig. 3.21):
Straight-leg jump – keep knees and ankles stiff.
Normal jump – bend knees and ankles naturally.
How did your ankle, knee, and hip positions differ between the two jumps?
Answer:
In a straight-leg jump, the ankle, knee, and hip joints remain stiff and straight, so there is very little or no bending. In a normal jump, the ankles, knees, and hips bend naturally. This helps absorb shock, maintain balance, and give better movement and height during the jump.
Question 5.
Which type of joint is involved when you bend your knees and ankles?
(i) Ball and socket
(ii) Hinge
(iii) Pivot
Answer:
(ii) Hinge
Question 6.
In each of the following cases (A, B, C, and D), choose the correct option as given below:
(i) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(iii) (A) is true, but (R) is false.
(iv) (A) is false, but (R) is true.
A. Assertion: Epithelium is well-suited for gas exchange in the lungs.
Reason: It consists of multiple layers of tall cells that slow down diffusion.
Answer:
(iii) (A) is true, but (R) is false.
B. Assertion: Cardiac muscle can contract continuously without fatigue.
Reason: Cardiac muscle cells have a high number of mitochondria and an abundant blood supply.
Answer:
(i) Both (A) and (R) are true, and (R) is the correct explanation of (A).
C. Assertion: Tendons connect bone to bone and allow joint movement.
Reason: Tendons are made of tough connective tissue that transmits force from muscle to bone.
Answer:
(iv) (A) is false, but (R) is true.
D. Assertion: In a hinge joint, movement occurs primarily in one plane.
Reason: The bone ends are shaped to allow sliding in all directions.
Answer:
(iii) (A) is true, but (R) is false.
Question 7.
Plot a graph between the age of a tree (in years) on the x-axis and the diameter of the tree (in cm) along with the number of annual rings formed over time on the y-axis, using the data given in the Table 3.7.
Table 3.7:
Data related to the age of a teak tree, and corresponding increase in the diameter of stem and number of annual rings
| Age of the teak tree (Years) | DBH (Diameter at Breast Height) tree (cm) | Number of annual of rings formed |
| 5 | 4 | 5 |
| 10 | 8 | 10 |
| 20 | 24 | 20 |
| 25 | 28 | 25 |
| 30 | 32 | 30 |
| 40 | 40 | 40 |
(i) Analyse the graph in terms of the diameter of the stem over time and share the interpretation.
(ii) What is the relation between the diameter of the teak tree to the annual rings formed?
(iii) Which specialised tissue is responsible for the girth of the stem, and where is it located?
Answer:
(i) Analysis of the graph:
The graph shows that as the age of the tree increases, the diameter of the stem also increases. The growth is gradual and continuous, indicating steady increase in girth over time.
(ii) Relation between diameter and annual rings:
There is a direct relationship between diameter and number of annual rings. As the number of annual rings increases, the diameter of the tree also increases, since each ring adds to the girth of the tree.
(iii) Specialised tissue and location:
The tissue responsible for the girth of the stem is the lateral meristem (cambium). It is located between xylem and phloem in the stem and is responsible for increase in girth (secondary growth).
Question 8.
In a forest, it was observed that one of the trees was severely debarked by an elephant to meet its food requirements, as the bark is a rich source of nutrients (Fig. 3.22). Based on your learning, answer the following:
(i) Which function(s) of the tree is/are hampered by debarking?
(ii) Which plant tissue would be affected by fig. 3.22? Further damage to the tree trunk even after debarking?
(iii) Which function of the tree would be hampered if the tissues beneath the bark were severely damaged?
(iv) What assumptions are you making to answer the questions above? How would the answer change if your assumptions are also changed?
Answer:
(i) Functions hampered by debarking:
Debarking damages the protective covering of the tree. As a result, the protection function is hampered. It also affects transport of food (phloem) and may indirectly affect the growth and survival.
(ii) Tissue affected by further damage to trunk after debarking:
If damage continues inward, the phloem (food-conducting tissue) and possibly Cambium (growth tissue) will also be affected.
(iii) Function hampered if tissues beneath bark are severely damaged:
If tissues beneath the bark (especially phloem and cambium) are damaged, the transport of food from leaves to other parts and growth in thickness (secondary growth) will be hampered. Eventually, the tree may die due to lack of food supply.
(iv) Assumptions and how answers may change:
We are assuming that only the bark is removed and the inner tissues are initially intact, and that damage does not immediately kill the tree. We also assume normal conditions for transport of water and food. If these assumptions change, for example, if the xylem is also damaged or the damage is very extensive, then water transport would also stop, leading to faster wilting and death of the tree.
Question 9.
Aamrapali observed that a young mango sapling’s stem bends flexibly during monsoon winds and does not break. Which tissue is responsible for this flexibility? Predict and provide your explanation of the impact if the existing tissue was replaced by sclerenchyma.
Answer:
The tissue responsible for the flexibility of the young mango sapling is collenchyma tissue. Collenchyma cells have unevenly thickened cell walls and are living in nature. This provides flexibility and mechanical support, allowing young stems and leaves to bend without breaking during strong winds.
If collenchyma were replaced by sclerenchyma:
Sclerenchyma cells are dead with thick, lignified walls, which provide rigid and hard support. If the sapling had scierenchyma instead of collenchyma, the stem would become hard and brittle, losing its flexibility. As a result, it would likely break easily in monsoon winds instead of bending safely.
Question 10.
Sohan designed an experiment for the regeneration of sugarcane, where he used cuttings to grow sugarcane. He used two types of cuttings, type ‘A’ and type ‘B’ (Fig. 3.23). After a few weeks, type ‘B’ cuttings sprouted and developed into sugarcane plants, whereas the type ‘A’ cuttings did not sprout.
(i) Why were the type ‘B’ cuttings able to grow as sugarcane, but type ‘A’ could not?
(ii) What difference was present in type ‘B’ compared to type ‘A’?
(iii) What observation or measurement was made to determine whether this Fig. 3.23 change had an effect?
(iv) What parameters should be kept the same for both types of cuttings to ensure a fair comparison?
Answer:
(i) Type ‘B’ cuttings grew because they had nodes, which contain buds (meristematic tissue) that can develop into new plants. Type ‘A’ had no nodes, so no new growth occurred.
(ii) Type ‘B’ had nodes with buds, while type ‘A’ had no nodes or buds.
(iii) The observation was whether the cuttings sprouted and developed into new plants. Type ‘B’ showed growth, while type ‘A’ did not.
(iv) Parameters to be kept the same (fair test):
- Same soil type
- Same amount of water
- Same sunlight
- Same temperature and environmental conditions
- Same size/length of cuttings.
Question 11.
During the discussion in class, Rohan gives a statement that “A tissue is a group of similar cells performing similar functions”. But Rajiv counter argues that, “this is true in case of simple tissues but little different in case of complex tissues”. Provide your explanation in view of the discussion in class.
Answer:
Rohan’s statement is correct for simple tissues. Simple tissues are made of similar types of cells performing the same function (e.g., parenchyma, collenchyma, sclerenchyma). However, Rajiv is also correct for complex tissues. Complex tissues are made of different types of cells that work together to perform a common function. For example, xylem and phloem consist of various kinds of cells, but together help in transport.
Question 12.
Coconut husk fibres are used for mats, which are tough and fibrous. Which tissue has structural features suitable for providing this strength? Explain why living parenchyma couldn’t serve the same purpose.
Answer:
The tissue responsible for providing strength to coconut husk fibres is sclerenchyma. Sclerenchyma are dead cells made of thick and lignified cell walls. These features make the fibres strong, rigid, and tough, which is suitable for making mats. Parenchyma cannot serve this purpose because its cells are living and have thin cell walls. They are soft and mainly meant for storage, so they cannot provide the required strength and toughness.
Question 13.
Vibha claims to her friend Neha that, “Meristematic cells are located only at the root and shoot apices”. What do you think about this statement? What question can Neha ask Vïbha to help her understand further if the statement is incorrect?
Answer:
Vibha’s statement is incorrect. Meristematic tissues are not only present at the root and shoot apices (apical meristem), but also in other regions, such as at nodes or base of leaves (intercalary meristem) and cambium (lateral meristem), responsible for increase in girth.
Question that Neha can ask:
“If meristematic cells are only at the apices, then how does the plant increase in thickness (girth) or regrow from other parts like nodes?”
Question 14.
A plant cell and an animal cell are of the same size.
(i) Which cell will have a larger vacuole? Give reasons.
(ii) What assumptions are you making to answer the question above?
Answer:
(i) The plant cell will have a larger vacuole.
Reason: Plant cells have a large central vacuole that stores water, nutrients, and wastes, and helps maintain turgidity and shape. Animal cells have small or no vacuoles.
(ii) Assumptions:
- The plant cell is a mature cell.
- Both cells are under normal conditions.
- We are comparing typical plant and animal cells.
Question 15.
A textbook states, “Each plant tissue performs only one specific function”. What questions would you ask to critically examine the correctness of this statement? What examples of tissues would you take to find out the answers to these questions?
Answer:
The statement is not completely correct, as some plant tissues perform more than one function.
Questions to examine the statement:
- Do all tissues perform only one function, or can they have multiple roles?
- Can a single tissue do both, support and store food?
- Do different cells within the same tissue perform different functions?
Examples to verify:
- Parenchyma: Performs storage, photosynthesis, and packing.
- Collenchyma: Provides support and flexibility.
- Xylem: Helps in water transport and support.
- Phloem: Transports food but involves different types of cells with different roles.
Class 9 Science Chapter 3 Tissues in Action Question Answer InText Questions
Think It Over (NCERT Textbook Page No. 28)
Question 1.
How is the study of cells and tissues significant for understanding the life processes and human welfare?
Answer:
The study of cells and tissues is important because these are the basic units of life that group together to perform similar functions.
It helps us understand life processes like respiration, digestion, and movement, as all activities occur at the cellular level and tissues perform specific functions. It is also important for human welfare, as it helps in diagnosing diseases, understanding problems like cancer, and developing treatments such as tissue repair and organ transplantation.
Question 2.
How are tissues in plants and animals different, and why?
Answer:
Plant and animal tissues differ in structure and function because their needs are different. In plants, tissues mostly provide support and growth. Many plant tissues are made of dead cells (like xylem that provides strength Plants do not move, so their tissues mainly help in transporting water, making food, and giving support.
In animals, tissues are made of Living cells and are more specialised. They help in movement. coordination, and quick responses. For example, muscle tissue helps in movement, and nervous tissue controls body activities.
Thus, tissues are different because plants are stationary and need support. while animals move and need coordination and quick actions.
Question 3.
How is the division of labour at various levels of organisation in multicellular organisms correlated with their structure and function?
Answer:
In multicellular organisms, division of labour means different parts perform specific functions, and this is closely linked to their structure.
- At the cellular level, cells are specialised in shape and structure to perform particular functions, like nerve cells for transmitting impulses.
- At the tissue level, similar cells group together to perform a common function, such as muscle tissue for movement.
- At the organ level, different tissues combine to form organs like the heart, which pumps blood.
- At the organ system level, organs work together, Like In the digestive system.
Thus, at each level, structure is adapted to function, ensuring efficient working of the organism.
Think It Over (NCERT Textbook Page No. 31)
Question 4.
Why do you think that the cell of meristematic tissues lack vacuoles?
Answer:
Meristematic cells lack large vacuoles because they are actively dividing and require all available space for dense cytoplasm and organelles like the nucleus.
Pause and Ponder (NCERT Textbook Page No. 33)
Question 1.
You may have noticed that fibres of coconut husk are hard and brittle, whereas the leaf stalks of coriander are soft and flexible. Find out the reason.
Answer:
The difference is due to the types of tissues present in them. Coconut husk contains sclerenchyma tissue, which has thick, lignified cell walls. These cells are dead and provide hardness and strength, making the fibres hard and brittle. On the other hand, coriander leaf stalk contains parenchyma and collenchyma tissues, which have thin or unevenly thickened cell walls. These cells are living and provide flexibility and softness.
Pause and Ponder (NCERT Textbook Page No. 34)
Question 2.
Why do you think that a thick cuticle on the outer wall of epidermis is advantageous for a plant living in the desert but disadvantageous for a plant living underwater?
Answer:
A cuticle is a waxy layer on the epidermis that reduces water loss. In desert plants, it is advantageous because it prevents excessive loss of water due to transpiration, helping the plant survive in dry conditions. In underwater plants, it is disadvantageous because it would prevent the absorption of water and dissolved gases from the surroundings, which these plants need for survival. Thus, the cuticle is useful in dry habitats but not suitable for aquatic plants.
Question 3.
Once water is absorbed by plant roots, it has to travel against gravity through xylem. How do the dead cells of the xylem work together with the living cells of leaves at the top to keep the water moving?
Answer:
Water moves upward in plants through a process called transpiration pull. The xylem is made of dead cells that form continuous hollow tubes, allowing water to pass easily from roots to leaves. In the leaves, living cells lose water through transpiration (evaporation from stomata). This Loss of water creates a suction force (pull) at the top, which pulls more water upward through the xylem. Cohesion (attraction between water molecules) and adhesion (attraction to xylem walls) help maintain a continuous water column. Thus, the dead xylem cells provide the pathway, while living leaf cells create the pull, working together to move water against gravity.
Question 4.
What do you think will happen if there were no stomata in the epidermis of the stem or leaves?
Answer:
If there were no stomata in the epidermis of stems or leaves:
Gas exchange would not occur, so carbon dioxide could not enter the plant for photosynthesis, and oxygen could not be released. Transpiration would stop, so there would be no transpiration pull to help in the upward movement of water. As a result, photosynthesis and water transport would be affected, and the plant would not survive properly.
Pause and Ponder (NCERT Textbook Page No. 40)
Question 5.
Look at the picture given below (Fig. 3.17). Carefully observe the various poses of classical and folk dances of India. Can you identify which joints are involved? Also, what type of movement each joint allows?
Answer:
In classical and folk dances of India, different body joints are involved to create various movements:
- Neck joint (pivot joint): Allows side-to-side movement, helping the body in smooth and controlled rotation around single axis.
- Shoulder joint (ball and socket joint): Allows movement in all directions (circular movement), helping in graceful arm movements
- Elbow joint (hinge joint): Allows back-and-forth movement, used in bending and straightening of arms.
- Wrist joint (gliding joint): Allows slight movements in different directions, important for hand gestures (mudras).
- Hip joint (ball and socket joint): Allows movement in all directions, helping in body bending and leg movements.
- Knee joint (hinge joint): Allows bending and straightening of legs, important for steps and jumps.
- Ankle joint (gliding Joint): Helps in foot movement and balance.
Think as a Scientist (NCERT Textbook Page No. 42)
(a) What do you conclude about the characteristics of phloem cells of the carrot?
(b) In which of the three combinations would you obtain the highest and lowest biomass? What could be the possible reason(s) for this observation?
(c) Will you get the same results if you culture animal cells instead of carrot cells?
(d) Think and mention any two commercial applications of the study above.
Answer:
(a) Conclusion about characteristics of carrot phloem cells:
Carrot phloem cells are totipotent. They are living cells that can dedifferentiate into unspecialised cells, divide actively, and then redifferentiate into all types of plant tissues to form a complete plant when provided with proper nutrients (sugars and hormones) and growth conditions.
(b) From the three combinations, the highest biomass would be obtained when:
Liquid medium + nutrients + light + air (all factors present). Lowest biomass would be obtained when: Solid medium + nutrients + light (no air).
Reason: The lack of air inhibit the cellular respiration, Light supports photosynthesis, and solid medium allows uptake of nutrients less efficiently than liquid medium, inhibiting the cell division.
(c) No, animal cells will not show the same result because they are generally not totipotent In mature stages. Unlike plant cells, most animal cells cannot differentiate and regenerate into a whole organism under normal culture
conditions.
(d) Two commercial applications:
- Micropropagation: Rapid production of large numbers of identical and desirable plants (e.g., orchids, bananas, sugarcane).
- Plant breeding and genetic engineering: Development of disease-resistant, high-yield, and improved crop varieties using tissue culture techniques.
Class 9 Science Chapter 3 Question Answer (Activities)
Activity 3.1:
Let Us Design Experiments (NCERT Textbook Page No. 29-30)
Aim: To study the role of root tips in the growth of roots in an onion bulb.
In Jar A (without cutting), roots continue to grow in length every day.
In Jar B (after cutting root tips), root growth either stops or becomes very slow.
Yes, the observations are similar to those presented in the graphical representation.
The difference clearly shows that root growth occurs only at the tips.
Conclusion: The experiment proves that roots grow only from their tips. The root tips contain actively dividing cells called apical meristem, which are responsible for the increase in length of roots. When the root tip is removed, these cells are destroyed and growth stops.
Activity 3.2:
Let Us Understand Further (NCERT Textbook Page No. 36)
Aim: To understand the role of blood and its components in different body responses such as injury, infection, and exercise.
1. Recall everyday experiences given in the first column of Table 3.3.
2. Write your observations and questions in your notebook.
3. Compare your observations with the observations given in Table 3.3. Do it yourself.
Observations:
Table 3.3: Your experiences, observations and questions from daily life (Answers may vary)
| Experiences | Observations | Questions |
| When you get a small cut on your skin | Red blood oozes out from the cut. A clot is formed after some time. | What causes blood to clot? |
| When you get a skin infection | The area turns red and perhaps slightly swollen. You may have a fever. | Why does swelling and redness occur infection? |
| When you exercise or run | You breathe faster. Your face may turn red. | Why does breathing rate increase during exercise? |
Activity 3.3:
Let Us Perform (NCERT Textbook Page No. 37)
Aim: To identify different connective tissues in the human body through simple daily life actions and understand their functions.
1. Perform the actions given in Table 3.4.
2. Record your experiences and compare them with the experiences given in Table 3.4.
3. Study their functions and identify the connective tissues (Fig. 3.12). (Refer to Table 3.4 and Fig. 3.12 of NCERT textbook) Do it yourself.
Bones have a rigid matrix containing calcium and phosphorus compounds, giving them strength and rigidity. In contrast, cartilage has a soft, jelly-like matrix and provides flexibility and cushioning. Other connective tissues include tendons and ligaments. Tendons connect muscles to bones, while ligaments connect bones to bones and prevent excessive movement (Fig. 3.12c).
Activity 3.4:
Let Us Investigate (NCERT Textbook Page No. 39)
Aim: To estimate the percentage of bones and muscles in the human body and compare it with total body weight.
Question.
Discuss why do bone and muscle mass differ between individuals, and how do they contribute to the overall body weight?
Answer:
Bone and muscle mass differ between individuals due to age, gender, genetics, nutrition, and level of physical activity. Growing children have less developed muscles and bones, while adults have more stable body composition. Regular exercise Increases muscle mass, while inactivity reduces it.
On average, bones form about 12-15% of body weight, and muscles form about 40-50% in adult males and about 30-40% in adult females. These tissues contribute to body weight by providing structure, support, movement, and strength. The remaining body weight includes fat, organs, blood, and water.
Activity 3.5:
Let Us Observe (NCERT Textbook Page No. 39)
Aim: To observe different types of movements performed by various parts of the human body and identify the type of joints involved.
Observations:
Table 3.5: Different types of movements our body can make
| Body Part | Complete Rotation | Partial Rotation | Bending | Turning, side-raising, up-down or any other movement |
| Elbow | No | No | Yes | bending and straightening |
| Shoulder | Yes | Yes | Yes | movement in all directions |
| Knee | No | No | Yes | Bending and Straightening |
| Neck | No | Yes | Yes | side – to – side movement |
| Fingers | No | No | Yes | bending and movement |
| Toes | No | No | Yes | slight bending |
| Wrist | No | Yes | Yes | movement in different directions |
Our answers are written in simple language, cover all important questions, and are perfect for quick revision. Whether you’re studying for unit tests or final exams, SchoolLearners provides reliable and student-friendly study material.
Visit schoollearners.in/ to access the complete Class 9 Science Chapter 3 Question Answer – Tissues in Action, along with NCERT Solutions, notes, MCQs, worksheets, and other useful resources for Class 9 students.