Answer:
<h2>Letter C</h2>
Cross training lets you include low-impact activities, like bike riding and swimming, that provide the benefits you need without putting more stress on your joints. Cross training can also help you recover from a back or knee injury.
I think it's health because it fits best in the sentence and situation
Teen years.
If you wait, it could be too late.
It's important now because in the long run, you won't have major signs of arthritis or common back problems.
For a child who follows a totally vegetarian diet, this is not a concern <span>Feeding problems may develop during the preschool years partially because of..</span>
