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]: To which group does an animal belong if it lays eggs and has scales and gills?  
 (A) amphibian (B) bird (C) fish (D) reptile
[A]: C


[Q]: In an experiment studying phototropism, students grew bean plants in labeled cardboard milk cartons. Afterward, the plants and soil were properly discarded. Which instruction line BEST conserves the remaining resources?  
 (A) recycle the markers, reuse the milk cartons (B) reuse the markers, discard the milk cartons (C) discard the markers, reuse the milk cartons (D) reuse the markers, recycle the milk cartons
[A]: D


[Q]: When astronauts walked on the Moon, they used weighted boots to help them walk due to the lower gravitational pull. What difference between Earth and the Moon accounts for the difference in gravity?  
 (A) density (B) diameter (C) mass (D) volume
[A]:
C