I would say the atmosphere because air and oxygen are essential for human life however it is debatable. You should check out this prezi and judge for yourself which sphere is effected the most from forest fires based on the descriptions on how a forest fire effects all four spheres.
https://prezi.com/m/50ogw-qsyoxc/the-four-spheres/
Answer:
Rain came along with lower temps
Explanation:
There was no rain on the warmer days
There were more clouds as the week went on
and the temp decreased during the week so rain came with lower temps is the only one that can be correct
