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.

Q: Which would most likely be the characteristic of an object with a small volume and large mass?  
 (A) high density (B) low pressure (C) low viscosity (D) high temperature

A: A
****
Q: Which of these will most likely harm a habitat?  
 (A) planting trees (B) water pollution (C) rainfall (D) sunlight

A: B
****
Q: Which two systems of the body are interacting when a runner sprains his ankle?  
 (A) the nervous system and the digestive system (B) the digestive system and the circulatory system (C) the respiratory system and the nervous system (D) the muscular system and the nervous system

A:
D
****