What prevents the backflow of blood inside the heart during contraction ? (a) thick muscular walls of ventricles (b) valves (c) thin walls of atria (d) all of the above

What prevents the backflow of blood inside the heart during contractio

1.	What prevents the backflow of blood inside the heart during contraction ? (a) thick muscular walls of ventricles (b) valves (c) thin walls of atria (d) all of the above
Answer» What prevents the backflow of blood inside the heart during contraction ? (a) thick muscular walls of ventricles (b) valves (c) thin walls of atria (d) all of the above