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]: A scientist studies the remains of two extinct animals to learn more about how they lived. She determines that one animal was a carnivore and the other was an herbivore. Which of the following did the scientist most likely compare to make this conclusion?
(A) the number of bones in the animals (B) the size of the animals (C) the body covering of the animals (D) the skull of the animals
[A]: D

[Q]: Many types of organisms live in a meadow. With the introduction of a large, swift-moving predator into the meadow ecosystem, which group of organisms will MOST likely have an advantage of surviving and reproducing?
(A) mice that have the thickest fur (B) foxes that have the largest ears (C) gophers that dig the deepest holes (D) rabbits that can run the fastest
[A]: D

[Q]: Which statement explains why a mother's unhealthy diet during pregnancy is harmful to her embryo's development?
(A) The embryo inherits half its chromosomes from its mother. (B) The embryo receives its food from its mother through the placenta. (C) The embryo receives oxygen through the placenta. (D) The embryo receives mutations carried by its mother.
[A]:
B