An air-pump is kept in an aquarium in order to

Options

A. make water cleaner
B. provide more carbon dioxide to water plants
C. allow more oxygen to dissolve In water
D. enhance the beauty of the aquarium

Answer

To solve the question regarding the purpose of an air pump in an aquarium, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Purpose of an Aquarium**:
- An aquarium is a controlled environment where fish and aquatic plants are kept. It requires a balance of oxygen and carbon dioxide for the health of the organisms inside.

**Hint**: Consider what living organisms need to survive in water.

2. **Identify the Function of an Air Pump**:
- An air pump is used to introduce air into the water. This process increases the oxygen levels in the water, which is crucial for the respiration of fish and other aquatic life.

**Hint**: Think about how fish breathe and what they need from the water.

3. **Evaluate the Options Given**:
- The options provided are:
a) Make water cleaner
b) Provide more carbon dioxide to water plants
c) Allow more oxygen to dissolve in water
d) Enhance the beauty of the aquarium

**Hint**: Analyze each option and determine which one relates directly to the function of an air pump.

4. **Select the Correct Option**:
- The correct option is **c) Allow more oxygen to dissolve in water**. This is because the primary function of the air pump is to increase the oxygen concentration in the water, which is essential for the survival of fish.

**Hint**: Focus on the needs of aquatic life and how the air pump helps meet those needs.

### Final Answer:
The air pump is kept in an aquarium in order to **allow more oxygen to dissolve in water** (Option C).