Draw a diagram of a male gametophyte of an angiosperm. Label any four parts. Why is sporopollenin considered the most resistant organic material ?

Explanation

### Step-by-Step Solution

**Step 1: Draw the Diagram of Male Gametophyte (Pollen Grain)**
Begin by sketching a simple oval shape to represent the pollen grain. This will serve as the outer structure of the male gametophyte.

**Step 2: Label the Outer Layer (Exine)**
On the outer surface of the oval, label the outer layer as "Exine." This layer is tough and discontinuous, primarily composed of sporopollenin.

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