If your training program is focused on improving how well your heart and
lungs work together to supply oxygen your body during exercise, what
health
related factor are you targeting?
The correct answer for the given question above would be the second option. If your training program is focused on improving how well your heart and lungs work together to supply oxygen to your body during exercise, then the related factor that you are targeting is cardiovascular efficiency. Cardiovascular efficiency measures how well your circulatory system is able to deliver oxygen to the rest of the body.
The heart is composed of two major loops. One going from your heart to your lungs, the other going from your heart to the rest of your body. When your heart beats, strong cardiac muscles pump blood to these destinations. I hope this helped.