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: All of the different organisms interacting in a pond make up  
 (A) a community (B) a population (C) the water cycle (D) the habitat

SOLUTION: A

PROBLEM: Evidence of organisms that lived on Earth a long time ago would most likely be found in  
 (A) crystals. (B) lava. (C) sedimentary rock. (D) metamorphic rock.

SOLUTION: C

PROBLEM: In order for magma to be converted to igneous rock, which actions must occur?  
 (A) melting and cooling (B) heating and pressure (C) weathering and erosion (D) crystallization and cooling

SOLUTION:
D