Animals/ organisms floating on the surface of water are

Options

A. plankton
B. pelagic
C. benthos
D. nektons

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about animals or organisms that float on the surface of water.

2. **Identifying the Correct Term**: The term used for organisms that float or drift on the surface of water is "plankton."

3. **Types of Plankton**:
- **Phytoplankton**: These are plant-like organisms, such as free-floating algae, diatoms, and dinoflagellates.
- **Zooplankton**: These are animal-like organisms, including protozoans, small crustaceans, and various invertebrate larvae.

4. **Explaining Other Related Terms**:
- **Pelagic**: This term refers to organisms that live in the upper part of the sea, which includes both zooplankton and nekton.
- **Nekton**: These are actively swimming organisms that can move independently of water currents.
- **Benthos**: These are organisms that live at the bottom of the water body, including decomposers like saprophytic bacteria and fungi.

5. **Conclusion**: The correct answer to the question is "plankton," specifically referring to both phytoplankton and zooplankton.

### Final Answer:
The animals/organisms floating on the surface of water are called **plankton**.

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