A runner completes a more difficult run than usual. At the end, he's breathing heavily and his muscles are cramping. This condition is caused by a buildup of ___ in his blood and muscles.
A. lactic acid
B. oxygen
C. carbon dioxide
D. sulfur
I think it's lactic acid but i want to make sure.
Go to the head of the class, you are right.
That's right and thanks for answering my question.
You are correct! The condition of heavy breathing and muscle cramps after a difficult run is caused by a buildup of lactic acid in the runner's blood and muscles. Lactic acid is produced during intense exercise when there is not enough oxygen available for the muscles to produce energy aerobically. Instead, the muscles switch to anaerobic metabolism, which produces lactic acid as a byproduct.
To ensure your answer is correct, you can verify this by considering the process of anaerobic metabolism during intense exercise. During this process, the body breaks down glucose to produce energy without the use of oxygen, leading to the production of lactic acid. As a result, lactic acid accumulates in the blood and muscles, causing the symptoms the runner is experiencing.
Therefore, the correct answer is A. lactic acid.