Explanation:
Flora- Flora is all the plant life present in a particular region or time, generally the naturally occurring native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms gut flora or skin flora.
Fauna- Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is flora, and for fungi, it is funga. Flora, fauna, funga and other forms of life are collectively referred to as biota.
The answer is a good luck
The troposphere because it has half of all air in the Atmosphere
I'm pretty sure A is the answer...
I hope this is correct and helps!