The contents of the closed boxes in each of the depictions below represents a system, and the arrows show the changes to the system during some process. Which of these processes is endothermic? 1.The first diagram has a box with 2 arrows heat(q) and work(w) leaving the box (system) to the surroundings. 2. The second diagram has one arrow representing work(w) going into the system from the surroundings. 3. The third diagram has one arrow representing heat (q) going into the system from the surroundings. The answer is the third diagram only. Why is it not the second and third diagram?