Question 3: Given an elevation h and a distance between the legs d, what happens if you increase the mass M of the glider? This question is talking about acceleration. Does it decrease, increase, etc.?

Answer: Doesn't change

Question 4: The gravitational acceleration can be determined from the slope of the graph of a vs. m/(M+m). What happens to the slope of the graph if you decrease the mass M of the glider?

Answer: Increases

Note: one of the answers is correct, I'm not sure which one and what the correct answer to the wrong one is.