Venous blood flows in the pulmonary arteries (from the right ventricle to the lungs). Entering the lungs, they branch into arterioles of a smaller diameter up to the capillaries. Passing through the capillaries of the lungs, the blood is saturated with oxygen (turns into arterial). Then, through the pulmonary veins, arterial blood enters the left atrium and ventricle.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.