You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

[Q]: In one area, a large source of prey for eagles is rabbits. If the number of rabbits suddenly decreases, what effect will it most likely have on the eagles?  
 (A) Their numbers will increase. (B) Their numbers will decrease. (C) They will adapt new behaviors. (D) They will migrate to new locations.
[A]: B


[Q]: Electron transport in mitochondria results in a chemiosmotic gradient of which particle across the mitochondrial membrane?  
 (A) ADP (B) ATP (C) protons (D) neutrons
[A]: C


[Q]: When studying planetary data, Jackie found some similarities and differences among the planets that make up the solar system. Which generalization is true about the orbits of the major planets in the solar system?  
 (A) Planetary orbits have the same plane. (B) Planetary orbits are mostly elliptical in shape. (C) Planets orbit at the same speed around the Sun. (D) Planets orbit in different directions around the Sun.
[A]:
B