when the factory puts that warm water into the stream where the fish live they changed their environment. by adding unknown chemicals and changing the temp of the water the fish start to die.
The fish aren't used to living in that warm water, and if they can't adapt fast enough they will die, also the unknown chemicals that could be in the water will act as a poison for them making that stream unable to support any life.
chemicals symbols are used for abbreviating the name of the element/chemical while chemicals formulas tell you how much of each element are in each chemical atom
I believe that it is A. If you remember in lesson 03.03 it gave multiple examples of things that support the continental drift theory. One of them was fossils of the same organisms found in different continents.
