So it could fit perfectly.
Answer:
A producer. For example in a common food chain, grass->grasshopper->mouse->snake->eagle. The grasshopper eats grass which is a producer so if there aren't anymore insects like grasshoppers, then the grass grows more.
Answer:
When he is swinging back up on the trapeze.
Explanation:
When he is swinging down, all the kinetic energy is being used. Once he begins his ascent, immediately after the halfway point, potential energy builds up once again.
