Science Que-Ans (Each of 2 Mark )

1. The main function of xylem is to carry water and mineral salts upward from the root to different parts of shoots.
2. Since walls of tracheids, vessels and sclerenchyma of xylem are lignified, they give mechanical strength to the plant body.

1. Cardiac muscles are involuntary muscles that contract rapidly, but do not get fatigued.
2. The cells of cardiac muscles are cylindrical, branched, and uninucleate.
3. They control the contraction and relaxation of the heart.

• Sieve tube.
• Companion cells.
• Phloem fibres.
• Phloem parenchyma.

• They are cylindrical and branched.
• They are uninucleated.
• Involuntary muscles.
• They contract and relax throughout life in rhythm.

1. Tracheids.
2. Vessels.
3. xylem parenchyma.
4. Xylem fibres.

• Skin: Stratified squamous epithelial tissue.
• Bark of tree: Simple permanent tissue.
• Bone: Connective tissue.
• Lining of kidney tubule: Cuboidal epithelial tissue.
• Vascular bundle: Complex permanent tissue.

1. They increase the absorptive surface of the intestinal cell (enterocyte).
2. They increase the surface area available for reactions.

1. Skeletal or striated muscle fibre is multinucleated.
2. Smooth or unstriated muscle fibre is long and spindle shape.

1. Plants are stationary or fixed as they don’t move while animlas move around in search of food, mates and shelter.
2. The growth in plants is limited to certain regions, while this is not so in animals.

1. Adipose tissues.
2. Ciliated epithelium.

1. Sclerenchyma fibers.
2. Sclereids.

Phloem is a vascular bundel in plants which helps in the transportation of food.

1. It helps in transpiration in plants.
2. It helps in exchanging gases with the atmosphere.
3. The gas exchange that occurs when stomata are open facilitates photosynthesis.

1. Intercalated discs.
2. Lignin.

1. Glandular epithelium is present in sweat gland.
2. Germinal epithelium is present in testis.

1. Parenchyma:

2. Collenchyma:

1. Xylem helps in conduction of water and minerals.
2. Phloem helps in conduction of food.

1. Apical meristem: It brings about the elongation of the root and stem.

2. Lateral meristem: It causes the organ (stem or root) to increase in diameter and girth.

1. Adipose tissue is the tissue that is filled with the fat globules and acts as an insulator.

Location of adipose tissue- It is present below the skin and in between the internal organs.

2. Cardiac muscles have cylindrical branched cells and shows rhythmic contraction and relaxation throughout the life.

Location- Cardiac muscle cells are present in heart.

• These cells provide protection for underlying tissues.
• They forms a barrier between the body and the exterior environment.
• Simple squamous epithelial cells(glomerulus) in nephrons of kidneys enable rapid filtration of blood and diffusion of small molecules.
• Squamous epithelial cells of lungs (alveoli of lungs) helps to reduce friction and controls vessel permeability.
• It also helps in absorption and filtration.

1. Tracheids.
2. Vessels or tracheae.
3. Xylem parenchyma.
4. Xylem Sclerenchyma.

Except xylem parenchyma, all other xylem elements are dead and bounded by thick lignified walls. Vessels are shorter and wider than tracheids. Vessels are very long tube-like structures formed by a row of cells placed end to end. Tracheids are elongated cells with tapering ends. They also conduct water.

1. They are highly specialised unit cells.
2. Neurons have the ability to receive stimuli from within or outside the body and to conduct (send) impulses (signals) to different parts of the body.

1. Meristematic tissue developed from parent cell.
2. Meristematic tissue take part in growth.
3. The place of injury is held up by the formation of new cell.