Final answer:
The scenario represents peer influence, with friends encouraging Rachel to join the cross country team for fitness and fun.
Step-by-step explanation:
The scenario where Rachel is encouraged by her friends to join the cross country team to become physically fit and have fun best represents peer influence or social influence. Her friends are implying that joining the team is a positive decision that leads to fun experiences and physical fitness. In the context of school and extracurricular activities, such encouragement among peers is common and can have a significant impact on students' choices and behaviors.
The scenario presented in the question represents the importance of physical fitness and the peer influence on health-related decisions. In this case, Rachel's friends are encouraging her to join the cross country team to improve her physical fitness. This situation highlights the social support and motivation that can come from participating in group activities.