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.
--------
Question: A scientific guess about the cause and effect of an event is called  
 (A) a variable. (B) a theory. (C) a hypothesis. (D) an observation.

Answer: C


Question: 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

Answer: A


Question: Plants use carbon dioxide from the atmosphere during the process of  
 (A) respiration. (B) fertilization. (C) evaporation. (D) photosynthesis.

Answer:
D