When a body is said to be in motion ? What do you mean by motion in one direction ?

Explanation

### Step-by-Step Solution:

1. **Definition of Motion**: A body is said to be in motion when its position changes with respect to its immediate surroundings. This means that if you observe an object and notice that it has moved from one place to another, it is considered to be in motion.

2. **Example of Motion**: For instance, if you are running and the trees around you remain stationary relative to your position, you are moving from point A to point B. In this case, your position is changing, indicating that you are in motion.

3. **Understanding Motion in One Direction**: Motion in one direction refers to the movement of an object along a straight path without changing its direction. This means that the object continues to move forward in a single line without veering off to the left or right.

...