C) Red Blood Cells
Red blood cells contains hemoglobin, which provide oxygen
Answer:
A form of high intensity interval training, CrossFit is a strength and conditioning workout that is made up of functional movement performed at a high intensity level.
Explanation:
I believe it’s carbon dioxide, because you use your respiratory system to breathe in oxygen, and oxygen goes through your circulatory system. And you breathe out CO2.
Answer: the heart, the blood vessel, and the blood itself
Explanation: hope this helps