What body part prevents food and liquid from going into the lungs?

Your epiglottis protects your ability to breathe by protecting your larynx (voice box). It keeps food and liquid from getting into your respiratory system. You can keep your epiglottis healthy by not smoking and protecting yourself from infection. When something affects your epiglottis, food, and fluid that should go down your esophagus end up in your larynx. Your body reacts by making you cough so your larynx can dislodge the food and fluid (food and liquid in your larynx may also make you choke).

Source: Cleveland Clinic