The exine of pollen grains (microspores) is composed of

Options

A. pollen kit
B. a-cellulose
C. sporopollenin
D. legnin

Answer

### Step-by-Step Solution:

1. **Understanding the Structure of Pollen Grains**:
- Pollen grains, also known as microspores, are the male gametophytes in flowering plants. They play a crucial role in the process of fertilization.

2. **Identifying the Exine**:
- The exine is the outer layer of the pollen grain. It serves as a protective covering that helps the pollen grain survive in various environmental conditions.

3. **Function of the Exine**:
- The primary function of the exine is to protect the pollen grain during its transport. Pollen grains can be carried by air, water, insects, birds, and animals, which necessitates a durable protective layer.

4. **Composition of the Exine**:
- The exine is composed of a highly resistant organic material known as **Sporopollenin**. This substance is known for its toughness and resilience.

5. **Properties of Sporopollenin**:
- Sporopollenin is resistant to degradation by enzymes, high temperatures, and extreme pH levels (both acidic and alkaline conditions). This makes it an ideal material for the exine, ensuring the pollen grain can survive various environmental challenges.

6. **Conclusion**:
- Therefore, the exine of pollen grains (microspores) is composed of **Sporopollenin**.