When the algae in a polluted river die, the population of which of the following organisms increases ?

Options

A. Fish
B. Frogs
C. Bacteria
D. Plankton

Answer

To solve the question "When the algae in a polluted river die, the population of which of the following organisms increases?", we can follow these steps:

### Step 1: Understand the Impact of Pollution on Algae
- Pollution in water bodies often leads to the overgrowth of algae, a phenomenon known as algal bloom. However, when the pollution becomes too severe, the algae can die off due to unfavorable conditions.

### Step 2: Identify the Role of Decomposers
- When algae die, they decompose. Decomposers, which include bacteria and fungi, play a crucial role in breaking down dead organic matter.

### Step 3: Recognize the Increase in Decomposer Population
- As the algae die and begin to decompose, the population of decomposers, particularly bacteria, will increase. This is because decomposers thrive on dead organic material, and the death of algae provides them with a new food source.

### Step 4: Conclude the Answer
- Therefore, the correct answer to the question is that the population of bacteria increases when the algae in a polluted river die.

### Final Answer:
The population of bacteria increases when the algae in a polluted river die.

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