Which environments were most common to find algae in? why do you think so?

In fresh, brackish or salt water. They are found both in tropical lakes and seas, and in the alpine and polar snows

Explanation:

They are unicellular or multicellular protist plant organisms, whose cells do not form tissues and lack flowers. They are considered the first link in the food chain in the aquatic environment. They are found in fresh, brackish or salt water. They are primary producers in the food chain, capable of producing organic substances through photosynthesis, so they use sunlight. They are found in tropical lakes and seas up to the alpine and polar snows.

I hope it is useful. Regards. María

i'd have to say the answer is probable the second option "the geosphere interacting with the atmosphere"

the answer is