Differentiate between the following:
$(a)$ Pollen tube and style.
$(b)$ Bud of Hydra and bud of Bryophyllum.

(N/A) The style is the elongated,slender stalk that connects the stigma to the ovary in a flower. The pollen tube is a tubular structure that emerges from the pollen grain after pollination and grows through the style to deliver male gametes to the ovary.
$(b)$ In Hydra,a bud is a small outgrowth formed by repeated mitotic cell divisions at a specific site on the parent body,which eventually detaches to form a new individual. In Bryophyllum,buds are adventitious buds that develop in the notches along the leaf margins; when these leaves fall on moist soil,the buds develop into new independent plants.