Each mouse in the study has brown ears.
Answer:
D
Explanation:
An infection is when something invades your body, therefore, you are infected with micro-organisms making it D.
It’s good to move around and touch things it builds you immune system.
Biome, though some might say ecosystem instead. Biomes are very large ecosystems that cover broad areas.<span>If they specify "one" reef, then they are probably looking for "ecosystem"</span>
