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.

Scientists use ice cores to identify and explain previous climatic trends. By correlating climatic conditions recorded in the ice, with solid, nonsnow particles also found in the ice, scientists can help to predict the climatic impact of which phenomena?  
 (A) atmospheric carbon dioxide concentration changes (B) radioactive decay rate changes in the outer core (C) volcanic eruptions (D) magnetic pole reversals
C

One hot summer, a grassland experienced a drought. Which most likely happened in the ecosystem during this time?  
 (A) The competition for food among primary consumers increased. (B) Nutrients cycled through the system at a faster rate. (C) Less solar radiation was able to enter the system. (D) Secondary consumers became extinct.
A

The sun is a star of average size and brightness. From Earth, the sun appears as a round, yellow object in the daytime sky. At night, we see other stars. They appear as tiny points of light. Why does the sun appear larger than stars that we see at night?  
 (A) Daylight brightens the sun, making it appear larger. (B) Starlight bends as it passes planets, making the stars appear smaller. (C) The sun is closer to Earth than other stars, making the sun appear larger. (D) Earth's atmosphere filters out light from other stars, making them appear smaller.

C