BIOLOGY [2 Mark Question Answer]

(i) Epidermis : epidermis is the outermost layer of skin on your body. It protects your body from harm, keeps your body hydrated, produces new skin cells and contains melanin, which determines the color of your skin
(ii) Cork-Cork is the outer protective layer of bark of a tree. The cork cells are dead and compactly packed with no intercellular space. Their cell walls are coated with a waxy substance, suberin, which do not allow water and gases to pass through

Sieve tubes have peripheral cytoplasm and large vacuole but lack a nucleus. Phloem companion cells are parenchymatous and these have a nucleus. These are also the living cells of phloem. Phloem fibers are dead

Tracheids, vessel elements and xylem fibers are dead cells of the xylem. The only living cells of xylem are parenchyma cells. Either tracheids or vessel elements are found in one xylem tissue. Living component of xylem is Xylem parenchyma

It is advantageous for an organism to be made of different kind of cells instead of one because different kinds of cells can do different jobs at a single time. Eg. - red blood works as a transportation medium. On the other hand white blood cells do different work at the same time.

Columnar Epithelium
squamous epithelium

Ciliated Epithelium
Squamous Epithelium