Class 9 Science Chapter 6 MCQ

Parenchyma cells from the bulk of the plant body. These cells are living and their possess the power of division. The cells are rounded, or isodiametric i.e. equally expanded on all sides. The cells are oval, ground, polygonal or elongated in shape with a thin cell wall. It encloses a dense cytoplasm, which contains small nucleus and surrounds large central vacuole.

Xylem vessels are very long tube-like structures formed by a row of cells placed end to end. The transverse walls between these cells are partially or completely dissolve to from continuous water channels. 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. Phloem fibres are thick walled, elongated, spindle shaped dead cells which possess narrow lumen. They provide mechanical support to the tissue. Phloem parenchyma are thin walled living cells of parenchyma. They have two functions, storage and lateral food conduction.

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.

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.

Cartilage is specialised connective tissue, which is compact and less vascular. The cartilage cells (chondroblasts) are widely spaced and the matrix is reinforced by fibres. Cartilage occurs at the joints of bones, in the nose, ear, trachea and larynx. It helps in smootheing the surface at the joints. It lends support and provide flexibility to the body parts.

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).

Skeletal muscles are striped, voluntary muscles, due to presence of alternate dark and light bands. They are called voluntary as they work according to our will. While doing work and running skeletal muscles contract and pull the tendon (which connects muscles to bones) to move the bone. Note: Smooth muscles are involuntary, i.e., they do not work according to our will, therefore option [A] and [B] cannot be the answer. Ligament connects bone to bone but it is the tendon which connect muscles to bones.

Sclerenchyma cells are the permanent tissues present in the plants. They provide hardness and stiffness to the plant and are composed of dead cells. This tissue is present in stems around vascular bundles in the veins of leaves and in hard covering of seeds and nuts. Example, the husk of coconut is made up of sclerenchymatous tissues. The cells of sclerenchyma are long narrow and thickened due to lignin.

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

Lymph is a colorless fluid that is filtered out of the blood capillaries and white blood cells are found in abundance.