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]: 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
[A]: D


[Q]: A dragonfly develops through incomplete metamorphosis. Which stages does the dragonfly's life cycle include?  
 (A) egg and larva (B) egg and nymph (C) larva and pupa (D) larva and nymph
[A]: B


[Q]: Which characteristic helps a fox find food?  
 (A) sense of smell (B) thick fur (C) long tail (D) pointed teeth
[A]:
A