Which one of the following shows the last diploid stage in the life cycle of angiosperms ?

Options

A. Pollen grain
B. Nucellus
C. Zygote
D. Microspore mother cell

Answer

To determine which structure represents the last diploid stage in the life cycle of angiosperms, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Life Cycle of Angiosperms**: Angiosperms undergo a complex life cycle that includes both diploid (2N) and haploid (N) stages. The diploid stage is represented by the sporophyte generation, while the haploid stage is represented by the gametophyte generation.

2. **Identify the Diploid Structures**: In angiosperms, the last diploid structures are the microspore mother cell (in male) and the megaspore mother cell (in female). Both of these cells are diploid (2N) and undergo meiosis to produce haploid spores.

3. **Meiosis and Gamete Formation**: The microspore mother cell undergoes meiosis to produce microspores, which develop into pollen grains (haploid). Similarly, the megaspore mother cell undergoes meiosis to produce megaspores, which develop into the female gametophyte (embryo sac).

4. **Formation of the Zygote**: Once fertilization occurs, the male gamete (from the pollen grain) fuses with the egg cell (from the embryo sac) to form a zygote. The zygote is the first diploid cell of the new sporophyte generation.

5. **Conclusion**: The last diploid stage before the formation of gametes is the microspore mother cell (in males) or the megaspore mother cell (in females). However, since the question asks for the last diploid stage in general, we can conclude that the microspore mother cell is often highlighted in the context of male gamete formation.

### Final Answer:
The last diploid stage in the life cycle of angiosperms is the **microspore mother cell**.

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