Small Intestine, mainly Jejunum and Ileum
<u><em>In most cases, it takes from 6 to 8 weeks for a stress fracture to heal. More serious stress fractures can take longer. Although it can be hard to be sidelined with an injury, returning to activity too soon can put you at risk for larger, harder-to-heal stress fractures and an even longer down time.</em></u>
Answer:
the awnser is dopamine. dopamine plays a role in the sensation known as pleasure .
According to AROUSAL approaches to motivation, each person strives to maintain a certain level of stimulation and activity.
