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: In what type of rock would a geologist most likely find evidence of ancient life?  
 (A) sedimentary (B) foliated (C) metamorphic (D) volcanic

SOLUTION: A

PROBLEM: What happens when water flows over a rock for a long period of time?  
 (A) erosion (B) flooding (C) breakage (D) evaporation

SOLUTION: A

PROBLEM: A greenhouse is an example of a closed system. Which two types of energy are exchanged in this system?  
 (A) radiant energy for nuclear energy (B) radiant energy for thermal energy (C) thermal energy for nuclear energy (D) nuclear energy for chemical energy

SOLUTION:
B