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 the morning, students observed puddles of water all over the playground. What would best explain why the playground was dry in the afternoon?  
 (A) Animals drank the water. (B) The wind stopped blowing. (C) Someone dried the puddles. (D) The water evaporated during the day.

SOLUTION: D

PROBLEM: Which difference between water and ice results in ice floating on cold water?  
 (A) heat (B) shape (C) density (D) volume

SOLUTION: C

PROBLEM: Human DNA includes a class of genes called "tumor suppressors." What do these genes do in bone cells?   
 (A) They restrict cell cycle progression in bone cells. (B) They promote the rapid development of bone cells. (C) They limit the number of bones in the human body. (D) They enable phosphorus and calcium to enter bone cells.

SOLUTION:
A