Final answer:
Participating in the Let's Move! campaign can help teenagers be role models for younger children in terms of nutrition.
Step-by-step explanation:
One activity that helps teenagers be a role model for younger for nutrition is participating in the Let's Move! campaign, launched by former First Lady Michelle Obama. This campaign aims to educate parents and caregivers on providing healthy nutrition and encouraging active lifestyles in future generations. By promoting healthy eating and physical activity, teenagers can serve as positive examples for younger children.