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: How do traits of animals such as ear shape, nose shape, and hair color most often get passed to offspring?  
 (A) sexual reproduction (B) asexual reproduction (C) adaptation (D) instinct

SOLUTION: A

PROBLEM: Which tool would be best to use for counting the number of legs on an ant?  
 (A) ruler (B) hand lens (C) calculator (D) microscope

SOLUTION: B

PROBLEM: Certain fossils can be used to help determine the age of the rock layer in which the fossils are found. Which type of fossil is best to use when making this determination?  
 (A) marine mammal fossil (B) swamp fern fossil (C) trace fossil (D) index fossil

SOLUTION:
D