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: Oxygen reacts with iron to produce rust and with hydrogen to produce water. Which statement describes both reactions?  
 (A) A different mixture is formed in each case. (B) A different solution is formed in each case. (C) Both a change of state and of elements is involved. (D) New molecules are formed but the same elements exist.

Answer: D


Question: The endangered Florida manatee is a large, aquatic mammal that feeds on sea grasses in brackish water. Due to where they like to feed, manatees are vulnerable to injuries from boat propellers. If speed zones requiring boats to maintain a low speed are placed in areas where manatees are known to congregate, which will most likely occur?  
 (A) less water pollution in manatee habitats will occur (B) manatees will seek alternate food sources (C) new manatee predators will surface (D) manatee populations will increase

Answer: D


Question: Which three systems of the human body function together to move and control body parts?  
 (A) nervous, skeletal, and muscular (B) muscular, endocrine, and excretory (C) digestive, excretory, and reproductive (D) circulatory, endocrine, and respiratory

Answer:
A