Shallow lakes with abundant organic matter are

Options

A. Saprotrophic
B. Oligotrophic
C. Eutrophic
D. Heterotrophic.

Answer

To answer the question "Shallow lakes with abundant organic matter are", we need to analyze the options provided and understand the characteristics of different types of lakes.

### Step-by-Step Solution:

1. **Understand the Question**: The question asks about shallow lakes that have a lot of organic matter. This implies we are looking for a specific type of lake that is rich in nutrients and organic materials.

2. **Evaluate the Options**:
- **Option A: Saprotrophic**: This term refers to organisms that feed on dead organic matter (detritus). While saprotrophic organisms may be present in lakes, the term does not describe the lake itself. Hence, this option is not correct.

- **Option B: Oligotrophic**: Oligotrophic lakes are characterized by low nutrient content and low primary productivity. They typically have clear waters and are not rich in organic matter. Therefore, this option is also incorrect.

- **Option C: Eutrophic**: Eutrophic lakes are shallow and have abundant organic matter and nutrients, particularly phosphorus and nitrogen. They often experience algal blooms and have poor water clarity. This matches the description given in the question, making this option correct.

- **Option D: Heterotrophic**: Heterotrophic refers to organisms that cannot produce their own food and rely on consuming other organisms. While heterotrophic conditions can exist in lakes, it does not specifically describe a lake with abundant organic matter. Thus, this option is incorrect.

3. **Conclusion**: Based on the analysis, the correct answer is **Eutrophic** lakes, as they are shallow lakes with abundant organic matter.

### Final Answer:
Shallow lakes with abundant organic matter are **Eutrophic**.

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