Trevor examines some water from the open ocean and finds that it contains several single-celled and multi-celled organisms. What term should Trevor use to describe the organisms based on their method of locomotion? Trevor should use the term to describe the organisms on the basis of their ability to move in water. Every time I try to put Pelagos, I get it wrong.

Mobility.

Explanation:

Mobility is the term used for all types of movement such as walking , running, swimming and flying etc. Mobility refer to the movement, those organisms which has the ability to move from one place to another is known as mobile organisms e.g lion, birds, tiger and humans etc, while on the other hand those organisms that are unable to move from place to place is called immobile organisms.

the sphincter muscles at the end of the digestive tract is the anus.

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