Final answer:
Parents should encourage their children to participate in physical activities.
Step-by-step explanation:
The sentence from the passage that best supports the statement that parents play an important part in making sure kids get exercise is: Parents should encourage their children to participate in physical activities. This sentence directly states that parents have a role in ensuring that their children engage in physical activities. Encouraging children to participate in physical activities can help them get the exercise they need for their overall health.