HI!
I am 99% sure cerebrum is your answer. Please tell me if I'm wrong.
Goo Day
Answer:
3 and 4
Explanation:
Both appear to be up river which mean they're coming DOWN to contaminate the uptake. If they're ahead of the uptake facility they're not going to show up in the water. I only know this because of City Skylines :)
The answer would be control because brain controls the body. everything you touch, taste, feel, hear, everything is controlled by the brain it is the thing that controls every other system in the human body.