Question

Chemicals from sea slugs may be useful in:

Answer 1

Chemicals from sea slugs may be useful in sewage treatment plants.The sewage treatment plants process includes  removing contaminants from wastewater, primarily from household sewage. The output of the sewage treatment process is treated wastewater that is safer for the environment.


SO BASICALLY ITS THE THIRD ANSWER

Answer 2

Chemicals from sea slugs may be useful in sewage treatment plants.
The sewage treatment plants process includes  removing contaminants from wastewater, primarily from household sewage. 
The output of the sewage treatment process is treated wastewater that is safer for the environment.