All of these.. Because it contains all of these characteristics
Incubation period: In medicine, the time from the moment of exposure to an infectious agent until signs and symptoms of the disease appear. For example, the incubation period of chickenpox is 14-16 days. In biology, the incubation period is the time needed for any particular process of development to take place.
2. improves the health of your muscles and I would think 1. considered exercise but the part with some of the time throws me off