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: Proxima Centauri is the closest star to the Sun. Which units do astronomers most often use for the distance between Earth and Proxima Centauri?  
 (A) miles (B) meters (C) light years (D) astronomical units

SOLUTION: C

PROBLEM: How do plants get water and minerals?  
 (A) absorbed from the soil though the roots (B) absorbed from the soil through the stem (C) absorbed from the air through the flowers (D) absorbed from the air through the leaves

SOLUTION: A

PROBLEM: Which of these would help determine the changes in a plant species over geologic time?  
 (A) examining the number of plants in a given area (B) examining the type of animals that eat the plant (C) examining the type of seeds the plant produces (D) examining the fossil record of the plant

SOLUTION:
D