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: One type of animal hatches from an egg, breathes through gills when it is young, and mainly lives on land as an adult. Into which group is this animal classified?  
 (A) amphibians (B) birds (C) mammals (D) reptiles

SOLUTION: A

PROBLEM: Some birds fly south in the fall and return in the spring. This is an example of  
 (A) migration (B) camouflage (C) hibernation (D) growth

SOLUTION: A

PROBLEM: El Niño is a term that refers to the oceanic phenomenon in which the surface water temperatures increase. The increase in water temperature usually occurs in the tropical Pacific Ocean. Which will most likely occur as a result of this phenomenon to cause environmental changes?  
 (A) melting of the polar ice caps (B) varied atmospheric conditions (C) an increase in volcanic eruptions (D) an increase in the length of summers

SOLUTION:
B