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.

Cuticle are protective, hydrophobic waxy covering produced by epidermal cells of leaves, young shoots and other aerial parts. It minimizes the water loss through transpiration (with the help of stomata) and also reduces pathogen entry. Lignin hardens the cell wall and provides flexibility, tensile and compressional strength to the cell wall. Suberin is present in cork cell and makes the cell impervious to water.

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. Tracheids and vessels are xylem elements and are concerned with the transport of water. They are long tube-like structures with partially or completely dissolved walls to from water pipes (in vessels) and pits in cell wall (in tracheids) for conducting water. Sieve tubes are slender tube-like structure with their end walls perforated by numerous pores and are called sieve plates. They are phloem elements and are main food conducting elements. Companion cells possess numerous mitochondria and ribosomes and are supporting units of sieve tubes. Note: Companion cells are associated with sieve tubes and connected to them by numerous plasmodesmata. They help in maintaining pressure gradient in sieve tubes. They are not perforated.

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.

Contractile proteins are found in muscles, as they are associated with the movement of body or limbs. The contraction and relaxation of contractile proteins, present in muscles bring about movement of limbs, internal organs etc. The bones are the major supporting tissues which form the endoskeleton of a vertebrate body. Blood is a fluid connective tissues responsible for transport of oxygen, nutrients, hormones etc. and for producing antitoxins and antibodies etc. Cartilage provides support and flexibility to the body parts and smoothens surface at joints. Note: Bones, blood and cartilage all are different types of connective tissues and are not responsible for movement of any of the body parts.

Dislocation of joints occurs when there is an abnormal separation in joint, which are held together by ligament. Therefore, ligament break and may result in dislocation of bone. Areolar tissues join skin to muscles, fills spaces inside organs and is found around muscles, blood vessels and nerves. Hence are not concerned with bones. Tendon break may cause inflammation and occurs due to factors including age, body weight, nutrition, sports etc. Note: Tendons joint skeletal muscles to bone and ligaments join bones 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.