Name the most resistant organic material known so far in nature and present in pollen grains.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of the most resistant organic material found in nature that is present in pollen grains.

2. **Identifying Pollen Grains**: Pollen grains are the male gametes in flowering plants and are produced in the anthers of flowers. They play a crucial role in the process of fertilization.

3. **Researching Organic Materials in Pollen**: Among the various components of pollen grains, we need to identify the specific organic material that is known for its resistance.

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