The answer is B. Digestive and cardiovascular
Answer:
B. An amino acid
Explanation:
Have a great day/night! :3
Answer:
They can make oxygen and they breathe in carbon so it helps reduce carbon but at the rate we make carbon it is too fast for the plants
Explanation:
1.The presence of valves 2.the milking action of skeletal muscles 3. the veins as the muscles contract