Maximum photosynthesis takes place by :

Options

A. Phytoplankton
B. Zooplankton
C. Marsh plants
D. Woody plants

Answer

To solve the question "Maximum photosynthesis takes place by:", we need to analyze the options provided and determine which group of organisms is responsible for the highest rate of photosynthesis on Earth.

### Step-by-Step Solution:

1. **Understanding Photosynthesis**:
- Photosynthesis is the process by which organisms convert light energy into chemical energy, using carbon dioxide and water to produce glucose and oxygen. It is primarily carried out by plants, algae, and some bacteria.

2. **Identifying the Options**:
- The options given are:
- A) Phytoplankton
- B) Zooplankton
- C) Marsh plants
- D) Woody plants

3. **Analyzing Phytoplankton**:
- Phytoplankton are microscopic marine algae that float in the ocean. They are primary producers in aquatic ecosystems and perform photosynthesis, contributing significantly to the global oxygen supply and carbon fixation.

4. **Analyzing Zooplankton**:
- Zooplankton are heterotrophic organisms that feed on phytoplankton and other small particles. They do not perform photosynthesis, so they cannot be responsible for maximum photosynthesis.

5. **Analyzing Marsh Plants**:
- Marsh plants are found in wetlands and do perform photosynthesis, but they are limited to specific environments and do not cover as much area as phytoplankton.

6. **Analyzing Woody Plants**:
- Woody plants, such as trees and shrubs, also perform photosynthesis. However, they are primarily terrestrial and do not match the vast numbers and coverage of phytoplankton in the oceans.

7. **Conclusion**:
- Since phytoplankton are the most abundant primary producers in the oceans, and oceans cover a significant portion of the Earth’s surface, it can be concluded that maximum photosynthesis occurs through phytoplankton.

### Final Answer:
**Maximum photosynthesis takes place by: A) Phytoplankton**

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