When a ball is dropped from a certain height the speed of the ball goes on increasing due to

Options

A. gravitational force
B. biological force
C. magnetic force
D. all of these.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Problem**: The question asks why the speed of a ball increases when it is dropped from a certain height. We need to identify the force responsible for this increase in speed.

2. **Analyzing the Options**:
- **Option A: Gravitational Force**: This is the force exerted by the Earth on the ball, pulling it downwards.
- **Option B: Biological Force**: This force relates to natural environmental factors and does not apply to the motion of the ball.
- **Option C: Magnetic Force**: This force acts between magnets and magnetic materials, which is not relevant to the ball falling.
- **Option D: All of These**: This option cannot be correct since options B and C do not apply.

3. **Eliminating Incorrect Options**:
- **Biological Force**: Since it does not affect the motion of the ball, we can eliminate this option.
- **Magnetic Force**: As the ball is not a magnetic material and does not interact with magnets in this context, we eliminate this option as well.
- **All of These**: Since both biological and magnetic forces are not relevant, this option is also eliminated.

4. **Identifying the Correct Answer**: The only remaining option is **Gravitational Force**. This force is responsible for the ball's acceleration towards the Earth, causing its speed to increase as it falls.

5. **Conclusion**: The speed of the ball increases due to the gravitational force acting on it as it falls towards the Earth.

**Final Answer**: The speed of the ball goes on increasing due to **gravitational force**.

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