While doing a controlled experiment, two groups must be set up. What are
these groups called?

To conduct a controlled experiment, two groups are needed: an experimental group and a control group. The experimental group is a group of individuals that are exposed to the factor being examined

Explanation:

volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. these particles serve as nuclei for the formation of water droplets (hydrosphere). rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere).

"it built up in the atmosphere"

i think thats it, idk, i tried looking for this exact q& a for grad. and idk if i got this question right or sorry if im wrong