When the semilunar valves are open, which of the following are occurring?
(1) coronary arteries fill
(2) AV valves are closed
(3) ventricles are in systole
(4) ventricles are in diastole
(5) blood enters aorta
(6) blood enters pulmonary arteries
(7) atria contract (a) 2, 3, 5, 6, (b) 1, 2, 3, 7, (c) 1, 3, 5, 6, (d) 2, 4, 5, 7.
The fact that the left ventricular wall is thicker than the right reveals that it (a) pumps a greater volume of blood, (b) pumps blood against greater resistance, (c) expands the thoracic cage, (d) pumps blood through a smaller valve.