The cardiovascular system, which transports blood through the body, is a one-way system.
t or f

True. Heart valves is responsible for the one way flow of blood through the champers of the heart. When functioning normally, one-way valves allows blood to flow from one chamber to another, or to flow out of the heart in one direction. The valves control blood flow by opening and closing during the contractions of the heart.

That is true! many fish species traveled to the u.s. because of it.