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: Which human organ system eliminates liquid and gaseous wastes from the body?  
 (A) circulatory (B) endocrine (C) excretory (D) reproductive

Answer: C


Question: What is the downward movement of water through pores and other spaces in soil due to the force of gravity?  
 (A) percolation (B) evaporation (C) precipitation (D) condensation

Answer: A


Question: Which environment is best for an organism that sleeps during the day and digs holes in the ground for shelter?  
 (A) wetland (B) rainforest (C) tundra (D) desert

Answer:
D