What happens to proteins within the endoplasmic reticulum? a. they are packaged. b. they are broken down. c. they are converted into lipids. d. they are modified by enzymes.

B. They are broken down.

Explanation:

     The rough endoplasmic reticulum, thanks to the presence of ribosomes, is responsible for much of the cell's protein production. The proteins manufactured in the RER ribosomes penetrate the pouches and move towards the Golgi apparatus, passing through the narrow and tortuous channels of the smooth endoplasmic reticulum.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."