B would be the most obvious option.
Answer: A.
increase the size of the muscle cells and the amount of blood that is delivered to the muscle
Explanation:
Increasing the size of the muscle cells and the amount of blood that is delivered to the muscle is important when it comes to muscular endurance.
The greater muscular endurance is the higher number of exercises that are including muscle effort against a force for a particular period of time.
High muscle endurance is helpful to the human body and immunity.
Same, I'm sick of school already and all the homework is just too much. But uhm you might wanna delete this before the mods do