Based on the information provided within the question it can be said that the best exercise that Mark's Doctor can suggest would be Aerobic exercise. These are exercises based on a set rhythm which increase strength as well as cardio-respiratory endurance. Meaning it will bring more oxygen to the body and increase stamina.
I believe the answer they are looking for is a 70year old would be covered by medicare as oppose to a 55year old with disablity would be covered by medicaid
