Why do submerged plants receive weaker illumination than exposed floating plants in a lake?

Explanation

### Step-by-Step Solution:

1. **Understanding the Environment**:
- In a lake, there are two types of plants: submerged plants (like Valisneria) that grow beneath the water surface and floating plants that are on the water surface.

2. **Light Penetration in Water**:
- Light travels through water but gets absorbed and scattered as it goes deeper. The intensity of light decreases with depth due to this absorption and scattering.

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