Blood saturated with carbon dioxide (venous) flows from the heart to the lungs through the efferent vessels (arteries). Conversely, from the lungs to the heart, oxygen-rich blood (arterial) enters the heart through the delivery vessels (veins). In a large circle that “serves” all organs of the body and carries oxygen, arterial (“oxygen”) blood runs through the arteries (from the heart), and venous (“carbonic”) runs back through the veins (to the heart).
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.