What must occur in order for matter to change states? A.
A chemical change must occur.
В.
The temperature must change.
C. Heat must be added or removed.
D.
Other substances must be added.

C. Heat must be added or removed

Explanation:

When matter changes states it is due to the overall loss or gain of heat. In addition, heat being added or removed is what will cause a temperature change, but a simple temperature change is not enough to change states. For example, a temperature could go from 50 degrees to 51. This will not cause a change in states. So heat must be added or removed in order for matter to change states.

8 m/s because for him to get the same amount of energy as ray is putting out, bobby, who weighs half as much as ray, needs to run twice as fast.