Developing a ( made absorption of nutrients more efficient for roundworms. coelom, anus, or mouth

The correct answer for the fill in the blank is Coelom.    

Coelom is a fluid filled body cavity in most of the animals that is present inside the body of the organism and has the digestive tract and different body organs of the system. Roundworms have definite digestive system that runs throughout the length of their body and includes mouth, pharynx, intestine, and anus.

The nutrients that are obtained after digestion of food are absorbed through digestive tract ( mainly from intestine).  

answer: blah

explanation:

bc blah

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.