TASK DEFINITION: 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.
PROBLEM: Which object is best used to demonstrate the bending of light as it passes through a substance?
(A) convex lens (B) flat mirror (C) opaque rod (D) concave mirror

SOLUTION: A

PROBLEM: How do most fish get the oxygen they need to survive?
(A) They take in water and break it down into hydrogen and oxygen. (B) Using their gills, they take in oxygen that is dissolved in water. (C) They get their oxygen from the food they eat. (D) They come to the surface every few minutes to breathe air into their lungs.

SOLUTION: B

PROBLEM: Maria Mitchell discovered a comet in 1847 that was later named after her. Maria Mitchell's discovery contributed to which branch of science?
(A) biology (B) chemistry (C) geology (D) astronomy

SOLUTION:
D