Final answer:
The main functions of the systems shown are: System A circulates blood and System B provides oxygen. The statement that best describes their functions is A) System A provides oxygen, while System B provides nutrients.
Step-by-step explanation:
The main functions of the systems shown are:
- System A circulates blood, which delivers oxygen and nutrients to cells.
- System B provides oxygen and removes waste products, such as carbon dioxide.
Thus, the statement that best describes the main functions of the systems shown is A) System A provides oxygen, while System B provides nutrients.