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: Which of these are scientific classifications for galaxies in the universe?  
 (A) dust, gas, ice (B) small, medium, large (C) spiral, elliptical, irregular (D) red giant, white dwarf, supernova

A: C
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Q: Which two processes occur during the life spans of all animals?  
 (A) hibernation and migration (B) growth and development (C) changing color and shedding fur (D) building nests and communication

A: B
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Q: The heart, veins, arteries, and capillaries make up which organ system?  
 (A) reproductive (B) muscular (C) excretory (D) circulatory

A:
D
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