Aerobic bacteria collect near illuminated phytoplankton due to

Options

A. Manufactured food
B. Light
C. Oxygen
D. Reduced `CO_(2)` concentration

Answer

### Step-by-Step Solution:

1. **Understanding Aerobic Bacteria**:
- Aerobic bacteria are organisms that require oxygen (O2) for their growth and metabolic processes. They thrive in environments where oxygen is available.

2. **Identifying Phytoplankton**:
- Phytoplankton are microscopic algae that float in water bodies. They perform photosynthesis, a process that converts carbon dioxide (CO2) and sunlight into glucose and oxygen (O2).

3. **Photosynthesis Process**:
- During photosynthesis, phytoplankton take in CO2 from the water and release O2 as a byproduct. This process is crucial as it contributes to the oxygen levels in aquatic environments.

4. **Reason for Bacterial Accumulation**:
- Aerobic bacteria are attracted to areas with high oxygen concentrations. Since phytoplankton release oxygen during photosynthesis, aerobic bacteria tend to collect around them to access this essential gas.

5. **Exclusion of Other Options**:
- The other options provided (manufactured food, light, and reduced CO2 concentration) do not explain the accumulation of aerobic bacteria near phytoplankton:
- **Manufactured Food**: While some bacteria can produce their own food, aerobic bacteria do not depend on phytoplankton for nutrition.
- **Light**: Although light is essential for photosynthesis, aerobic bacteria can obtain light independently and do not need phytoplankton for this purpose.
- **Reduced CO2 Concentration**: Aerobic bacteria do not require CO2 for their growth; they need oxygen.

6. **Conclusion**:
- The primary reason aerobic bacteria collect near illuminated phytoplankton is the availability of oxygen released during the photosynthesis process of the phytoplankton.

### Final Answer:
Aerobic bacteria collect near illuminated phytoplankton due to the oxygen released by phytoplankton during photosynthesis.

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