Final answer:
I would change the types of exercises included in the cross-training challenge to provide a more diverse and well-rounded workout for students.
Step-by-step explanation:
If I could change any part of the cross-training challenge in physical education, I would choose option b) The types of exercises included.
By changing the types of exercises included in the challenge, we can provide a more diverse and well-rounded workout for students.
This can help them develop different skills and target various muscle groups. For example, we could include exercises like burpees, lunges, push-ups, and planks to focus on different areas of fitness such as strength, endurance, and flexibility.