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: When do mutations help make an ecosystem more sustainable?  
 (A) when mutations decrease the number of individuals in an ecosystem (B) when mutations increase the number of individuals in an ecosystem (C) when mutations decrease the number of species in an ecosystem (D) when mutations increase the number of species in an ecosystem

Answer: D


Question: What tool would be used to examine a fingerprint?  
 (A) a graduated cylinder (B) a hand lens (C) a pair of goggles (D) a thermometer

Answer: B


Question: One advantage of a hand lens over a microscope is that the hand lens  
 (A) is easier to carry on field investigations. (B) is less likely to be infected by bacteria. (C) makes very tiny objects appear larger. (D) produces a more accurate image.

Answer:
A