SOMEONE PLS HELP ME PLS P. S. on the pink one i just need help with the evidence and reasoning

heres the link to the newsela article

https://newsela. com/read/voyager-2-message/id/20000 01658/

Afive-year study was carried out on a population of algae in a lake. the study found that the algae population was steadily decreasing in size. over the five-year period this decrease most likely led to