What can you say about the motion of a body if its speed-time is a straight line parallel to the time axis?

Give one example of a motion where an object does not change its speed but its direction of motion changes continuously.

Name the type of motion in which a body has a constant speed but not constant velocity.

What conclusion can you draw about the speed of a body from the following distance-time graph:

What can you say about the motion of a body whose distance time graph is a straight line parallel to the time axis?