Water hyacinth floats on the water surface. Explain.

$(a)$ State the constituents of phloem.
$(b)$ How does cork act as a protective tissue?

$(a)$ What is the function of the tissue present in the bark of a tree?
$(b)$ Which substance is present in the adipocyte? How does it help?

$(a)$ Give reasons for the following:
$(i)$ Multicellular organisms are considered more efficient.
$(ii)$ Sclerenchyma cells have a narrow lumen.
$(iii)$ Epidermis is thicker in desert plants though it is usually single layered.
$(b)$ Name the following:
$(i)$ Tissue that occurs in specific regions of growth.
$(ii)$ Tissue present at the growing tips of stems and roots.
$(iii)$ Tissue at the base of the leaves or internodes on twigs.
$(iv)$ Basic packing tissue in the form of a few layers of cells.

Give reasons for the following:
$(i)$ Bark of a tree is impervious to gases and water.
$(ii)$ In desert plants,epidermis has a thick waxy coating.
$(iii)$ Epidermal cells of the roots generally have hair-like parts.

Animal tissues are different from plant tissues. State the reasons.