Help and pls explain how you know.

Right ventricle, Semi-lunar valve, Pulmonary artery, Lungs

Explanation:

In order to know the answer, it is best to know the actual flow of blood which is from the right side of the heart towards the left side. This is called a circulatory process because it is being repeated over and over again within the body.

Remember that blood coming from the right atrium goes to the right ventricle through the tricuspid valve. Here, the blood waits to be filled and once it is full, it flows to the pulmonary semilunar valve. This valve allows the blood to leave the heart. Then, it goes to the pulmonary artery. After which, it goes to the lungs. From here, it is oxygenated.