Class 9 Science Chapter 6 MCQ

The conducting tissues in plants conduct different shapes and have different structures. The primary conducting tissues of plants are xylem and phloem. Xylem conducts water from roots to the other parts of the plant, whereas phloem transports food and other material from the leaves to other parts of plants.

Chlorenchyma consists of living cells and are characterized by the presence of cellulose. Chlorenchyma is a mechanical tissue in young dicotyledonous stems and provides mechanical support and elasticity. It provides great tensile strength with flexibility to those organs in which it is found. It allows easy bending in various plants of a plant mainly young growing stream without breaking them.

The matrix of cartilage has delicate network of collagen fibres and chondrocytes (living cells). These are present in fluid-filled spaces called lacunae. Chondrocytes multiply by mitosis and help in internal growth of cartilage. A mast cell is a resident granulocyte of several types of tissues. It contains granules rich in histamine and heparin. They play a key role in allergy and are involved in wound healing and defence against pathogens. Basophils are granulocytes of white blood cells (WBCs) and are involves in functions of body defence by engulfing bacteria and other foreign substances. Osteocytes are the bone cells.

Each nerve cell or neuron is composed of three parts. i)Cyton or cell body: It contains central nucleus and cytoplasm with characteristic deeply stained particles called “Nissl’s granules” (i.e. clumps of ribosome). ii) Dendron: These are short processes arising from cyton and further branching into dendrities. ii)Axon : It is a single long cylindrical process of uniform diameter which forms fine branches terminally. The dendrites receives impulses and the axon takes impulses away from the cell the body. Tendon are the connective tissue, which join skeletal muscles to bones, hence nervous tissue is absent is them. Nervous tissue is specialized to transmit messages within our body. It contains highly specialized unit cells called nerve cells or neurons. They have the ability to receive stimuli from within or out-side the body and to conduct (send) impulses (signals) to different parts of the body. Brain, spinal cord are all associated with the regulation of body activity and are composed of nervous tissue.

Voluntary muscles are the muscles, which are under our complete control for e.g., the working and movement of limbs. On the other hand, involuntary muscles are controlled by hypothalamus i.e., they are regulated rhythmically, e.g., alimentary canal, iris of the eye and bronchi of lungs. Note: Alimentary canal, iris of the eye and bronchi of lungs, the movements of the above organs are not under our will.

Tendons are cord-like, strong, inelastic, structures that join skeletal muscles to bones. A tendon is a white fibrous tissue which has great strength but limited flexibility. It consists of parallel bundles of collagen fibres, between which are present, rows of fibroblasts (called tendinocytes).

Smooth muscles are found in the walls of hollow visceral organs. They do not work according to our will. They are involved in peristaltic movement of gastro-intestinal tract and male genital tract. Cardiac muscles are present in the heart. They contract and relax rapidly, rhythmically and tirelessly. They help to pump the blood to various parts of the body. The working of both smooth and cardiac muscles is involuntary while skeletal or straited in muscles are moving to our will and are voluntary in action.

Explanation: Parenchyma serves as the packing tissue in plants therefore they do not have intercellular spaces. Collenchymatous tissues are mechanical tissues in the plants and are characterized by the deposition of cellulose at the corners of the cell, which leads to localised thickening of the cell wall. Apical and intercalary meristem bring primary growth (increase in height) and secondary growth (increase in diameter) respectively and are classified under meristematic tissues. Meristematic tissues are dividing units of the plants and contain dense cytoplasm and large nucleus with few or no vacuoles at all.

Here, all these statements are correct. Hence, your answer will be option [D].

Here, all these statements are correct. Hence, your answer will be option [D].