Which of the following is called eutrophication?
Deterioration of water quality due to organic matter
Deterioration of water due to accumulation of algae
Improvement in quality of water due to dissolved oxygen
Deterioration of water quality of water body because of enrichment with nutrients

Options

A. Deterioration of water quality due to organic matter
B. Deterioration of water due to accumulation of algae
C. Improvement in quality of water due to dissolved oxygen
D. Deterioration of water quality of water body because of enrichment with nutrients

Answer

To determine which option is called eutrophication, let's analyze each option step by step:

### Step 1: Understand Eutrophication
Eutrophication is a process where water bodies become overly enriched with nutrients, particularly nitrogen and phosphorus. This leads to excessive growth of algae and aquatic plants.

### Step 2: Analyze the Options
1. **Deterioration of water quality due to organic matter**: This option mentions organic matter, but eutrophication is primarily caused by inorganic nutrients (nitrogen and phosphorus), so this is not the correct answer.

2. **Deterioration of water due to accumulation of algae**: While excessive algae growth is a result of eutrophication, this option does not fully capture the cause of the process, which is nutrient enrichment. Thus, this is not the best answer.

3. **Improvement in quality of water due to dissolved oxygen**: This option is incorrect because eutrophication leads to a decrease in dissolved oxygen levels, which deteriorates water quality, not improves it.

4. **Deterioration of water quality of water body because of enrichment with nutrients**: This option accurately describes eutrophication as it highlights the deterioration of water quality due to nutrient enrichment.

### Conclusion
The correct answer is: **Deterioration of water quality of water body because of enrichment with nutrients.**

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