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: The body is made up of many systems that interact with one another. For example, the skeletal system and the muscular system work together to help the body move. Which system works with the respiratory system to distribute oxygen to the body?
(A) muscular system (B) digestive system (C) lymphatic system (D) circulatory system

SOLUTION: D

PROBLEM: A leaf is covered in mud during a landslide. After one million years, this leaf will most likely be ___.
(A) a fossil (B) an animal species (C) a new plant species (D) a nonrenewable fuel

SOLUTION: A

PROBLEM: Which statement describes a function of bones in mammals such as dogs and horses?
(A) Bones provide protection for organs in the body. (B) Bones send messages to the brain to move the muscles. (C) Bones carry oxygen-rich blood throughout the body. (D) Bones connect the brain and the spinal cord.

SOLUTION:
A