instruction:
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:
Soil will pack down over time which decreases the ability of the soil to hold water. Which animals would best help the soil hold water?  
 (A) earthworms making tunnels under the surface (B) cattle making depressions with their hooves (C) horses making trenches when they gallop (D) sheep pulling up plants by their roots
answer:
A


question:
Strong winds have the ability to uproot large trees in a wooded area. Which of these organisms would most likely benefit from this change in a habitat?  
 (A) a bee colony that needs a hive (B) a bird that needs to build a nest (C) a squirrel that needs to find shelter (D) a plant that needs sunlight to grow
answer:
D


question:
When light reflects off certain crystals in the atmosphere, effects called halos appear. Which substance in the atmosphere forms these crystals?  
 (A) carbon dioxide (B) oxygen (C) sulfur dioxide (D) water
answer:

D