Metabolic threshold. it’s switching from one function to the other
We get tired after exercise because our muscle fibers get tired very quickly. This is due to the major source of energy for the muscle tissue, called adenosine triphosphate, or ATP. As the muscles make use of this supply of energy, they get tired and fatigue.
The answer is A.
Hope this helps!
What’s the code and i’ll join
OK so basically the location of the sinoatrial node will be in the right atrium
