Cells present in the mature pollen grains are _______.

The correct option is Vegetative cell and generative cell.

In angiosperms (flowering plants), the development of a pollen grain (microgametophyte) involves the division of the microspore. During this process, the microspore undergoes an asymmetric mitotic division to produce two distinct cells within the mature pollen grain:

1. Vegetative Cell: This is the larger cell. It contains abundant food reserves and a large, irregularly shaped nucleus. Its primary function is to give rise to the pollen tube, which delivers the male gametes to the female gametophyte during fertilization.

2. Generative Cell: This is the smaller cell. It floats within the cytoplasm of the vegetative cell. The generative cell eventually divides mitotically to produce two male gametes (sperm cells).

Therefore, the cells present in the mature pollen grains are the vegetative cell and the generative cell.