Describe how to recognize an emergency and size up the scene. ■■ Explain how to activate and work with the emergency medical services (EMS) system. ■■ Understand legal concepts as they apply to lay responders, including consent and the purpose of Good Samaritan laws. ■■ Identify how to reduce the risk of disease transmission when giving care. ■■ Demonstrate how to check a person who is responsive for life-threatening and non-life-threatening conditions. ■■ Explain how to check an injured or ill person who appears to be unresponsive. ■■ Recognize the signs and symptoms of a heart attack, and describe appropriate first aid care for a person who is showing these signs and symptoms. ■■ Describe the links in the Cardiac Chain of Survival. ■■ Demonstrate CPR and use of an automated external defibrillator (AED) for a person who is in cardiac arrest.