What is pollen-pistil interaction in flowering plants?

Explanation

### Step-by-Step Solution

1. **Definition of Pollen-Pistil Interaction**:
- Pollen-pistil interaction refers to the specific biological processes that occur when pollen grains land on the stigma of a flower's pistil. This interaction is crucial for sexual reproduction in flowering plants.

2. **Pollination Process**:
- Pollination occurs when pollen grains are transferred to the stigma, which is the receptive part of the pistil. This can happen through various agents such as wind, insects, or water.

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