Option A,
both limit movement of substances through the system
The sphincter muscle usually surrounds the openings in the body such as urethra, anus and performs the function of tightly closing the openings. When once the messages are received from the nervous system the sphincter relaxes and releases the material out of the opening during urination of excreting
The same is the function of valves in the circulatory system. They also prohibits the entry of blood from one chamber to other and then to the main circulatory system. The relaxes on receiving a signal from the brain and thus transfer blood from one chamber to the other.
The question is not worded the best but the answer is C. Trait
Answer:
The Atom is the basic unit of matter
Explanation:
just cuz
