(a) Explain the development of female gametophyte from a megaspore mother cell in an angiosperm.
(b) Draw a labelled diagram of a fully developed embryo sac.

Explanation

### Step-by-Step Solution

**(a) Development of Female Gametophyte from a Megaspore Mother Cell in Angiosperms:**

1. **Location of Female Gametophyte Development**: In angiosperms, the female gametophyte, known as the embryo sac, develops within the ovule, which is located in the ovary of the carpel (or pistil) of the flower.

2. **Formation of Megaspore Mother Cell**: Inside the ovule, there is a mass of cells called the megasporangium. One of these cells differentiates into the megaspore mother cell (2n), which is large, has dense cytoplasm, and a prominent nucleus.

...