I believe the answer would be hypothesis. Because it's the students suggestion. He still doesn't know for sure so it's not the conclusion. The experiment was already given so it can't be that and the student isn't taking anything out of the experiment so it's not a deduction.
Oxygen and nutrients are transported around an animal's body by the circulatory system.
<span>Circulatory system or cardiovascular system includes the circulating blood with the role in the transport of nutrients oxygen, carbon dioxide, hormones, and blood cells. Besides the transport function, it also stabilizes temperature and pH, and maintain homeostasis. The circulatory system is divided into <span>a systemic circulation and a pulmonary circulation.</span></span>