Give reasons for

(a) Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole.

(b) Intercellular spaces are absent in sclerenchymatous tissues.

(c) We get a crunchy and granular feeling, when we chew pear fruit.

(d) Branches of a tree move and bend freely in high wind velocity.

(a) Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole . These cells are undifferentiated and continue dividing. They lack vacuole, because they do not store food or cell sap.

(b) Sclerenchyma tissue is tough and provide mechanical strength. The cells are lignified, and hence intercellular spaces are absent giving rigidity and elasticity to plant to withstand various stains.

(c) The cell walls of sclerenchyma are greatly thick due to presence of ligins. Ligin is a complex polymer with high tensile strength and does not break easily thus we get a crunchy and granular feeling, when we chew pear fruit.

(d) Branches of a tree move and bend freely in high wind velocity due to presence of collenchyma’s tissue. These are characterized by the deposition of extra cellulose at corners of the cell here intercellular spaces are absent and cells are elongated.