Q: Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.
Your respiratory system is made up of the tissues and organs that allow oxygen to enter your body and carbon dioxide to leave your body. Organs in your respiratory system include your: Nose. Mouth. Larynx. Pharynx. Lungs. Diaphragm. The organs of the respiratory system move air into and out of the body. These structures are shown below (Figure 1.1). What do you think is the purpose of each of these organs? The nose and the nasal cavity filter, warm, and moisten the air you breathe. The nose hairs and the mucus produced by the cells in the nose catch particles in the air and keep them from entering the lungs. Behind the nasal cavity, air passes through the pharynx, a long tube. Both food and air pass through the pharynx. The larynx, also called the "voice box," is found just below the pharynx. Your voice comes from your larynx. Air from the lungs passes across thin tissues in the larynx and produces sound. The trachea, or windpipe, is a long tube that leads down to the lungs, where it divides into the right and left bronchi. The bronchi branch out into smaller bronchioles in each lung. There is small flap called the epiglottis that covers your trachea when you eat or drink. The muscle controlling the epiglottis is involuntary and prevents food from entering your lungs or wind pipe. The bronchioles lead to the alveoli. Alveoli are the little sacs at the end of the bronchioles (Figure 1.2). They look like little bunches of grapes. Oxygen is exchanged for carbon dioxide in the alveoli. That means oxygen enters the blood, and carbon dioxide moves out of the blood. The gases are exchanged between the blood and alveoli by simple diffusion. The diaphragm is a sheet of muscle that spreads across the bottom of the rib cage. When the diaphragm contracts, the chest volume gets larger, and the lungs take in air. When the diaphragm relaxes, the chest volume gets smaller, and air is pushed out of the lungs. "Grape-like" alveoli in the lungs.
A:
what keeps food out of the lungs?