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:
Ella waves good-bye from the bus. What body system pulls on bones to let Ella wave her arm?  
 (A) muscular system (B) nervous system (C) digestive system (D) circulatory system
answer:
A


question:
Animals get energy for growth and repair from  
 (A) soil (B) food (C) water (D) air
answer:
B


question:
Which mechanism helps carbon to cycle from the atmosphere to living organisms?  
 (A) tissue decomposition (B) cellular respiration (C) photosynthesis (D) transpiration
answer:

C