Blood is propelled back to the heart by ________.
A)rhythmic contractions of muscles in the walls of veins and the action of one-way valves
B)skeletal muscle contractions around veins and the action of one-way valves
C)the negative pressure of the heart pulling blood into the empty chambers
D)the natural flow of blood into ever-larger blood vessels leading to the heart

Question

Quizplus · Accepted Answer

Skeletal muscle contractions around veins and the action of one-way valves help propel blood back to the heart. The muscles squeeze the veins, pushing blood towards the heart, while the one-way valves prevent backflow of blood.

Blood Is Propelled Back to the Heart by ________