A. the runner's muscles have accumulated lactic acid.. I think. 99% sure
Voltage sources are uses to sustain the flow of protons chemical reactions resistance in the movement of electric charge.
Answer:
It means when cells make protein
Explanation:
Answer:Muscles relax and contract when one muscle pulls and moves your body part and if you want to do the opposite movement the opposite muscle contracts, allowing the first muscle to relax.
Explanation: