How can teens demonstrate good physical fitness to their families? by keeping their rooms tidy
by flossing their teeth every day
by saying and you
by taking the stairs instead of the elevator

The correct answer is D.

Taking the stairs instead of the elevator is a form of physical activity and will help fitness levels. If teens walked up and down the stairs on a regular basis instead of taking the elevator this would show to their families that they are demonstrating good fitness levels and are not being lazy.