Answer:
Your muscles will require less oxygen to move and they will produce less carbon dioxide. This will immediately reduce the amount of air you will need to breathe in and out for a given exercise.
Allergies, so they don't ingest something they are allergic to.
The corticospinal tract carries motor signals from the primary motor cortex in the brain, down the spinal cord, to the muscles of the trunk and limbs. And The corticobulbar tract carries efferent, motor, information from the primary motor cortex to the muscles of the face, head and neck.
