Respuesta :
1. right atrium
2. aortic valve
im not sure if that is the answer
thats what i got
Answer:
The blood enters the right artrium.The Presence of valves prevents backflow of blood.
Explanation:
The heart is a muscular organ, blood enters the heart through two large veins that is superior and inferior vena cava. Valves opens and close tightly, as heart pumps the blood, the valves prevent the blood to stop flowing in the backward direction. There are two main valves which is tricuspid valve and bicuspid valve. It helps in preventing back flow. The tricuspid valve is present in between right atrium and ventricle. The biscuspid valve is present in between left ventricle and left atrium.