Because they have the nutrients humans need to survive, if you stopped eating vegetables you'd get really weak.
Because it is easier to have a chain of command established with the staff if only one person is the leader. Companies and corporations also save money in the practice of only having a single leader or "boss."
I don't know if that answer will exactly help. :)
Answer:
Yoga
Explanation:
Yoga works flexibility and breathing and is not a form of a respiratory workout option.