Which of the following is a way that muscle fibers get energy needed for contraction? 1) when a muscle is contracting during peak activity, it quickly uses up stored creatine phosphate which was produced during moderate exercise. 2) during moderate exercise, such as jogging on the treadmill, pyruvate and hydrogen ions accumulate causing muscle fatigue. 3) during peak activity levels, glycolysis is the only pathway by which atp can be produced to supply energy to the muscle. 4) because energy demands are low in a resting muscle, a resting muscle is able to meet its atp requirement through glycolysis. 5) aerobic exercise is beneficial to a muscle because it increases muscle's ability to acquire greater amounts of glucose from

The correct option is number 3.

Explanation:

ATP serves as the main energy molecule in our bodies. Although our body can store ATP but the  requirement of energy at the time of high activity or exercise is more as compared to the stored amount of ATP. Hence, our bodies tend to produce ATP by the cycle of glycolysis. In glycolysis, glucose is broken down to yield pyruvate molecules with the release of ATP ( energy ) molecules.

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americans began to notice growing differences between the northern and southern sections of the country. there were more people living in cities in the north, which made it more urban. more people lived on farms in the south, which made it more rural. while many people were farmers in the northern states, there were now other ways to make a living, such as working in mechanical cotton gins factories manufacturing cloth, tools and other goods. people in the north supported high tariffs on goods imported from europe because the extra cost encouraged people to “buy american” instead. in the southern states, planters did not like tariffs because they sold most of their production to europe and bought their tools from there as well. southerners believed the protective tariff was something that only northern factory owners keep their profits high. so the southern politicians came up with an idea. they would opt out. they would simply ignore the protective tariff. it was ‘null and void’ in south carolina. the state would not collect the taxes on goods imported into south carolina, no matter what the president said they had to do. this decision led to the nullification crisis.