<span>The question is asking us what is BEST to say about a runner who is running at a constant velocity? A constant velocity (=speed) means that they are not getting faster or slower - they are running exactly as fast all the time. This meanst that their speed does not change, so their change of speed is equal to 0. A change of speed is called acceleration so their C. Their acceleration is zero. - C is the correct answer. </span>
A. A fast moving stream. Water has erode Earth for thousands of years. This was what caused the Grand Canyon. A faster ,owing stream would cause a faster erosion due to the speed and strength of the water itself.
