1. Plants possess three main types of meristematic tissues: apical, lateral, and intercalary.
2. Apical meristems are at root and shoot tips, promoting growth in length. Lateral meristems are along the circumference of stems, increasing girth.
3. Intercalary meristems are at the base of internodes or nodes, enabling regrowth after cutting or grazing, prominent in plants like grasses.

1. Phloem is a complex permanent tissue. It is a conducting tissue found in plants, made up of four types of elements: sieve tubes, companion cells, phloem fibres, and phloem parenchyma.
2. Sieve tubes are tubular cells with perforated walls. Companion cells are closely associated with the development and function of sieve tubes.
3. Phloem transports food (translocation) from the leaves to other parts of the plant and can move materials in both directions. Except for phloem fibres, all phloem cells are living.

1. (i) The given figures are of tracheids (a) and vessels (b) of xylem tissue.

(ii) Differences

1. (iii) Tracheids and vessels are lignified tissues that provide mechanical strength to the plant body. They also carry water and mineral salts from roots to different parts of the plant vertically.

1. Xylem tissue is formed of four types of elements: tracheids, vessels, xylem parenchyma and xylem fibres.

1. Meristematic tissues continuously generate new cells. While some retain their meristematic capacity, others undergo a process called differentiation.
2. During differentiation, these new cells lose their ability to divide and change their structure and function.
3. They specialize to perform specific roles such as support, transport, or storage, thereby forming the various permanent tissues found throughout the plant body.

1. The plant will die within a few days of re-plantation. Since the root tips have been cut, the roots will not grow due to the absence of meristematic tissue.
2. When the roots of the plant do not grow, proper absorption of water and minerals will not occur, leading to the death of the plant.

1. The muscles which do not move on our will are called involuntary muscles. These muscles are also called smooth muscles. We cannot move them or stop them at will.
2. They are found in the alimentary canal, blood vessels, ciliary muscles of the eye, ureters and bronchi of the lungs. The movement of food in the alimentary canal or the contraction and relaxation of blood vessels are involuntary movements.

1. Dislocation of the bones of the hand may have been caused due to the breakage of the ligament.
2. A ligament is a connective tissue that connects two bones and keeps them in place.

1. The framework of bones forming the skeletal system is the primary structural component.
2. It provides the body with its shape, maintains its posture, and offers crucial protection to soft, delicate internal organs like the brain, heart, and lungs. Without this bony framework, the body would lack structural integrity and be highly vulnerable to injury.

1. If there were no stomata: gas exchange would not occur, so CO₂ cannot enter and photosynthesis stops, and there would be no oxygen release.
2. There would also be no transpiration, so no cooling and no upward pull of water — transport of water and minerals would get affected.
3. Ultimately, the plant would not survive.

1. In a multicellular organism, cells become specialized to perform different functions. Different functions are taken up by different groups of cells, and accordingly, the cells become morphologically different.
2. This phenomenon of taking up a permanent shape, size, and function by a meristematic tissue is known as differentiation. Permanent tissues lose the ability to divide.

1. An epithelial cell sometimes acquires additional specialisation as a gland cell. Gland cells can secrete substances at the surface of the epithelium.
2. A multicellular gland or glandular epithelium is formed when a portion of the epithelial tissue folds inward.

1. The pivot joint in the neck is specially designed to allow the head to rotate side to side. In this joint, one bone moves around another, similar to how a doorknob turns.
2. This helps the skull move over the backbone, enabling us to shake our head to say "no".
3. At the same time, it limits movement in other directions, providing stability and protecting the brain while allowing necessary motion for daily activities.

1. Differentiation is the process where cells, initially derived from meristematic tissues, lose their ability to divide and undergo structural and functional changes to become specialized.
2. These specialized cells then form permanent tissues, each performing a unique role within the plant, such as support, transport, or storage.
3. This process is significant because it allows the plant to develop complex organ systems and perform diverse physiological functions efficiently, moving beyond simple active division to create a robust and functional organism.

1. Tissue responsible: Sclerenchyma.
2. Coconut husk fibres are tough because sclerenchyma cells have thick, lignified cell walls that provide great mechanical strength and rigidity.

Why not parenchyma?

1. Living parenchyma cells have thin cell walls and are soft, so they cannot provide the strength and toughness required for fibres like coconut husk.

1. Vibha's statement is incorrect. Meristematic tissues are not only present at root and shoot apices (apical meristem), but also as:
2. Intercalary meristem (at nodes/internodes), and Lateral meristem (cambium, for increase in girth).

Question Neha can ask

1. "If meristematic cells are only at apices, then how does a plant increase in thickness (girth)?"

1. (i) The plant cell will have a larger vacuole. This is because plant cells typically contain a large central vacuole that maintains turgor pressure, storage, and support. Animal cells either have small vacuoles or none.

(ii) Assumptions

1. Both cells are typical, mature cells with no special modifications (like storage cells, etc.), and under normal conditions where plant cells maintain turgidity.

1. If a unicellular organism developed distinct tissues, its functions would become more specialized and efficient. Different tissues would perform specific roles such as digestion, communication, and movement.
2. This division of labour would improve resource use and response to environmental changes, allowing the organism to adopt better survival strategies like finding food or avoiding danger.
3. Overall, it would function more like a multicellular organism, relying on coordination between tissues for survival.

1. The musculoskeletal system provides structural support, helping maintain posture and enabling the body to stand upright.
2. It protects internal organs, with the skull safeguarding the brain and the rib cage protecting the heart and lungs.
3. It also enables movement and locomotion, allowing activities like walking and running. Additionally, its functioning is coordinated by the nervous system, ensuring proper control and integration of body movements.

1. Voluntary movements are actions under conscious control, such as walking or writing, and are carried out by skeletal muscles. These muscles are striated and attached to bones.
2. Involuntary movements occur automatically, like digestion and heartbeat. Smooth muscles control movements in organs like the stomach, while cardiac muscles regulate heartbeats.
3. These movements are controlled by the nervous system without conscious effort.

1. (i) In the given diagram of the epidermis, A represents the epidermal cells of the roots that bear long hair-like parts called root hairs. With the help of these cells, root hairs greatly increase the total absorptive surface area and help in water absorption.
2. (ii) B represents the stomata. Stomata are the pores present in the epidermis of the leaves. They help in the exchange of gases with the atmosphere during photosynthesis and respiration. Also, the process of transpiration (loss of water in the form of water vapour) takes place through stomata.
3. (iii) Cell C represents the guard cells. These are kidney-shaped cells that enclose the stomata and thus help in the opening and closing of stomata.

1. (i) The given image shows adipose connective tissue.
2. (ii) Adipose connective tissue is found below the skin and between internal organs.
3. (iii) The cells of adipose connective tissue are filled with fat globules. The storage of fats allows it to act as an insulator.

1. (i) The tissue shown is collenchyma tissue. Labels: A – Wall thickenings, B – Nucleus, C – Vacuole, D – Cell wall.
2. (ii) Yes, the collenchyma tissue is flexible. This is because collenchyma cells don't have lignin in their cell wall.

(iii) Functions

1. Collenchyma tissue provides flexibility to the plant.
2. It also provides mechanical support to plants.

1. The absence of a rigid cell wall in animal cells provides flexibility, allowing them to change shape easily. This flexibility supports locomotion by enabling coordinated movements such as muscular contractions.
2. In contrast, plant cells have a rigid cell wall that maintains shape and provides structural support, but restricts movement.
3. As a result, plants remain fixed in one place, while animals can move freely. This structural difference directly influences their modes of life and mobility.

1. Hinge joints, such as the elbow or knee, allow movement in only one plane, mainly bending and straightening. They provide stability but restrict rotation and sideways movement.
2. Ball and socket joints, like the shoulder, allow movement in multiple directions. Their structure enables forward, backward, sideways, and circular motion.
3. Therefore, hinge joints support limited movement, while ball and socket joints provide greater flexibility and a wider range of motion.

1. Division of labor in multicellular organisms refers to the specialization of tissues to perform specific functions, improving overall efficiency.
2. In animals, muscle tissue enables movement while nervous tissue transmits signals. In plants, xylem transports water and minerals, and phloem carries food.
3. This specialization ensures that each tissue performs a particular role instead of handling all functions, allowing organisms to carry out complex processes more effectively, supporting survival, growth, and proper functioning.

1. Movement in the musculoskeletal system is a synergistic process involving muscles, tendons, and bones. Muscles are the active contractile units; when a muscle receives a signal from the nervous system, it contracts.
2. This contractile force is then efficiently transmitted to the bones through strong, flexible connective tissues called tendons.
3. Tendons act as intermediaries, pulling on the bones. This pulling action at a joint causes the bone to pivot, resulting in observable movement.

1. (i) The skeletal system provides support, protection, and structure to the body. It helps maintain posture, protects internal organs, and works with muscles and joints to enable movement and flexibility.
2. (ii) The rib cage protects the heart and lungs. It consists of 12 pairs of ribs that form a protective framework around these vital organs, preventing injury and supporting breathing movements.
3. (iii) The rib cage helps in breathing by expanding and contracting due to flexible cartilage connections. This movement increases and decreases the chest space, allowing air to enter and exit the lungs efficiently during respiration.

OR

1. Maintaining bone health is important because strong bones support the body, protect organs, and enable movement. Proper nutrition, exercise, and practices like yoga help keep bones strong, joints flexible, and prevent injuries or disorders.

1. (i) Apical Meristem is responsible for the growth of the tip of stem and root.
2. (ii) Parenchyma tissue; in aquatic plants, large air cavities are present in parenchyma (called aerenchyma) to give buoyancy to the plant and help it float.
3. (iii) Collenchyma tissue provides flexibility.

OR

1. The husk of the coconut is hard and stiff because it is made up of sclerenchymatous tissue. The cells of this tissue are dead and are long and narrow, as the wall is thickened due to lignin.

1. (i) Collenchyma provides flexibility in plants.
2. (ii) No, aerenchyma helps aquatic plants to float (it does not provide mechanical support).
3. (iii) No, apical and intercalary meristems are not permanent tissue.

OR

1. The tissue shown (sclerenchyma) provides strength to the plant parts.

1. (i) The cell shown in the figure is a Tracheid.
2. (ii) Cuticles reduce the loss of water in desert plants.
3. (iii) Phloem fibres are the dead element present in the phloem.

OR

1. Yes, cardiac muscle is an involuntary muscle. The muscles whose functioning cannot be controlled by our will are called involuntary muscles.

1. (i) Meristematic tissues are plant tissues made up of actively dividing cells. These cells continuously divide to produce new cells, helping in plant growth in terms of length, thickness, and regeneration after damage.
2. (ii) The apical meristem helps in increasing plant length. It is located at the tips of roots and shoots and contains actively dividing cells that contribute to elongation growth.
3. (iii) Different meristems contribute to plant growth in various ways. Apical meristem increases length, lateral meristem increases girth, and intercalary meristem helps in regrowth after cutting. Together, they ensure overall growth and development of the plant.

OR

1. Differentiation is the process by which meristematic cells lose their ability to divide and become specialised in structure and function. These cells form permanent tissues that perform specific roles like support, transport, and storage in plants.

1. (a) Connective
2. (b) Stomata
3. (c) Columnar epithelium
4. (d) Respiratory tract
5. (e) Sclerenchyma

1. (i) The vertebral column provides crucial structural support for the entire body, enabling an upright posture and facilitating movement. The rib cage, acting as a protective enclosure, shields vital internal organs like the heart and lungs from external damage and plays a key role in the mechanics of breathing. Together, they form a robust framework for the torso.
2. (ii) The spinal column achieves both strength and flexibility through its layered construction. Individual vertebrae provide segments of strength and articulate with each other. Between these rigid vertebrae, cartilage discs serve as flexible cushions, allowing for a range of motion while absorbing compressive forces. This unique combination ensures the column can support significant weight and allow for bending and twisting movements without damaging the internal spinal cord.
3. (iii) The rib cage is structurally designed to fulfill both protective and respiratory functions. Its framework of 12 pairs of ribs, securely attached to the spine and sternum, creates a strong, protective cage around the heart and lungs. At the same time, the flexible cartilage connecting the ribs allows for rhythmic expansion and contraction. This flexibility is essential for altering the volume of the chest cavity, thereby enabling the movement of air in and out of the lungs during respiration.

Striated muscle

1. The cells of striated muscle fibres are long or elongated, non-tapering and cylindrical and unbranched. These cells have a number of nuclei. These muscle fibres show alternate dark and light bands or striations (under the microscope) and hence are called striated muscles. They occur in muscles of limbs, body wall, face, neck, etc.

Functions of striated muscles

1. They are powerful and undergo rapid contraction. They are also called skeletal muscles.
2. They provide the force for locomotion and all other voluntary movements of the body. Hence, they are also called voluntary muscles.

Smooth (unstriated) muscle

1. Some muscles do not bear any bands, stripes or striations across them (under the microscope), and hence are called smooth or unstriated muscles. The cells of these muscle fibres are uninucleate.
2. Smooth muscles occur as bundles or sheets of elongated fusiform or spindle-shaped cells or fibres, held together by loose connective tissues. They are found in the walls of internal organs such as the alimentary canal, stomach, intestine, ureters, bronchi, iris of the eye, ducts of glands and blood vessels.

Functions of smooth muscles

1. They do not work according to our will, so they are also called involuntary muscles. Movement of food in the alimentary canal or the contraction and relaxation of blood vessels are involuntary movements.
2. They contract slowly but can remain contracted for a long period of time. The ingested food passes to the next step of digestion in the alimentary canal due to this characteristic.

1. (i) A hinge joint is mainly distinguished by allowing movement in only one plane. It permits bending and straightening movements, known as flexion and extension. Unlike ball and socket joints, it does not allow rotation or sideways movement, which gives the joint greater stability and controlled motion.
2. (ii) A common anatomical location of a hinge joint, apart from the elbow, is the knee. The knee joint allows the lower leg to bend and straighten for walking, running, and sitting. It mainly moves in one direction, similar to the opening and closing of a door hinge.
3. (iii) A hinge joint has bones arranged in a way that one bone fits into the curved surface of another, like a door hinge. This design allows movement only forward and backward. Sideways movement and rotation are prevented, so the joint moves only in a single plane.

1. Yes, we can control some of the actions of our body, but some are not under our control. The actions which we can control are known as voluntary actions, like the movement of hand and limbs. We can move these parts of our body whenever we want to.
2. But some actions of our body, like contraction and relaxation of the heart, blinking of an eye, etc., are not under our will — i.e. we cannot stop the functioning of the heart even if we want to.
3. The muscles which can perform voluntary actions are voluntary muscles, also called skeletal muscles or striated muscles. These muscles are mostly attached to bones and help in body movement. Their cells are long, cylindrical, unbranched and multinucleate (having many nuclei).
4. The actions which are not under our control are known as involuntary actions. These are performed by smooth muscles or involuntary muscles. Their cells are long with pointed ends (spindle-shaped) and uninucleate (single nucleus).