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.

Cellulose is a basic of the cell wall present in plants. The cell wall of almost all the organisms are made up of cellulose whereas lipids along with some proteins forms the basic building blocks of plasma membrane. Plasma membrane is semi-permeable and it is not impervious to water. Lignin is a complex polymer which acts as a cement and hardens the cell wall. It provides flexibility, great tensile and compressional strength to the cell wall and makes the cell wall impermeable. It is present in sclerenchyma cells and not in cork cells. The walls of cork cells are heavily thickened with an organic substance, suberin. Suberin makes these cells impervious to water and gases.

Companion cells are present along the sieve tube are connected to them via plasmodesmata. These cells are metabolically active and sieve tube elements are dependent on these cells. They do not lose nuclear nucleus at maturity. RBC vessels and sieve tube cells lose their nucleus at maturity.

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.

dipose tissue consists of oval and round cells filled with fat globules, scattered in the matrix. This tissue is found below the skin, between internal organs and in the yellow bone marrow. It stores fat and acts as an insulator. Cuboidal epithelium help in absorption, excretion and secretion, whereas bones and cartilage are specialized connective tissue and they provide support to the internal organs.

Meristematic tissues consists of actively dividing cells and is present in the growing region of plants, e.g. tips of roots and stems. The cells of meristematic tissue are round, oval, polygonal or rectangular. They are packed closely without intercellular spaces, have him cellulose walls, dense cytoplasm and prominent nuclei. Vacuoles are almost absent in such cells because they are completely filled with sap.

Columnar epithelium consists of pillar-like cells with their nuclei towards the base. They form the lining of stomach, small intestine and colon, forming the mucous membrane. Their main function is absorption (e.g. stomach, intestine) and secretion (e.g. mucus by goblet cells). Stratified squamous epithelium, also known as pavement epithelium is covered by fibrous protein, (keratin) that covers the skin. This epithelium is waterproof and resistant to mechanical injury. Cuboidal epithelium is found in kidney tubules, thyroid vesicles and in glands.

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].