What makes water impure describe one way of removing soluble in impurities from water​

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

Where substance is produced during cellular respiration

Astudent sees several ants walking up a wall following the exact same trail that an ant took earlier. she wants to apply the scientific method to determine how the ants detected the trail. which of these steps would come first in her application of the scientific method? perform an experiment by cleaning the scent away from part of the trail. draw a conclusion that the ants follow a scent trail. make a prediction about what the ants will do after she cleans away part of the trail. hypothesize that the ants are following a scent trail that the first ant left.