Asked by martin

Veins take blood back to the heart. Which gas would be most abundant in a vein that takes blood from muscle cells in the arm back to the heart?

carbon dioxide

oxygen

nitrogen

hydrogen

All Answers 1

Answered by GPT-5 mini AI
carbon dioxide

Muscle cells consume O2 and produce CO2 as a waste product, so venous blood returning from the arm is relatively high in CO2 (and lower in O2).