Answer the following question given this paragraph: Figure 32.7 Pollen develops from the microspore mother cells. The mature pollen grain is composed of two cells: the pollen tube cell and the generative cell, which is inside the tube cell. The pollen grain has two coverings: an inner layer (intine) and an outer layer (exine). The inset scanning electron micrograph shows Arabidopsis lyrata pollen grains. (credit "pollen micrograph": modification of work by Robert R. Wise; scale-bar data from Matt Russell). Q: The mature pollen grain is composed of two cells: the pollen tube cell and which other cell? A:
Available options:
(A). ova;
(B). glial cell;
(C). photosynthesis cell;
(D). generative cell;
(D).