The chemical responsible for fossilisation of pollen grains is

Options

A. Sporopollenin
B. Pollenkit
C. Lignin
D. Carotenoids

Answer

To answer the question regarding the chemical responsible for the fossilization of pollen grains, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Pollen Grains**:
- Pollen grains are the male gametes in flowering plants. They are typically spherical in shape and have a diameter ranging from 25 to 50 micrometers.

2. **Structure of Pollen Grains**:
- Pollen grains consist of two main layers: an outer layer and an inner layer. The outer layer is known as the exine, while the inner layer is called the intine.

3. **Identifying the Outer Layer**:
- The outer layer (exine) of the pollen grain is primarily composed of a chemical called sporopollenin.

4. **Properties of Sporopollenin**:
- Sporopollenin is recognized as one of the most resistant organic materials. It has the ability to withstand extreme conditions, including high temperatures and strong acids and alkalis.

5. **Importance of Sporopollenin**:
- Due to its remarkable resistance, sporopollenin is crucial for the preservation of pollen grains over geological time, making it a key factor in the fossilization process.

6. **Conclusion**:
- Therefore, the chemical responsible for the fossilization of pollen grains is **sporopollenin**.

### Final Answer:
The chemical responsible for the fossilization of pollen grains is **sporopollenin**.

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