Answer: B - transports oxygen and carbon dioxide for the respiratory system
The cardiovascular system consists in the heart and all blood vessels. Blood vessels lead the blood from the heart to the rest of the body and then brings it back. It's in the lungs, part of the respiratory system, where the gas exchange is going to happen. What that means is that oxygen is going to enter the blood while the carbon dioxide needs to be eliminated.
(If the option A, said carries hormones FROM the endocrine system, that would be also correct.)
The answer is D, white blood cells.
The main function of white blood cells is to defense the body from bacteria or other pathogens. There's 2 main kinds of white blood cells, lymphocytes and phagocytes. Lymphocytes mainly produce antibodies that can kill bacteria or any pathogens, and phagocytes can ingest the pathogens directly.
Therefore, since the white blood cells can protect our body, they're part of our immune system.
The answer is B. This is because baby dolphins, when born, can't really comprehend a lot of things yet, so they, and the more adult dolphins there, try to get to the surface of the ocean to take a breath. :D I hope I helped!
Brain controls nerves
Heart pumps the blood
