You will be given a definition of a task first, then some input of the task.
Based on the information present in the given passage, you need to write a correct answer to the given question. A correct answer is one that correctly and completely answers the question. Do not write answers that address the question partially or incorrectly. The correct answer must be contained in the given paragraph.

Paragraph- Sent 1: Breathing is the process of moving air into and out of the lungs.
Sent 2: The process depends on a muscle called the diaphragm.
Sent 3: This is a large, sheet-like muscle below the lungs.
Sent 4: Inhaling, or breathing in, occurs when the diaphragm muscle tightens.
Sent 5: This increases the size of the chest.
Sent 6: This too decreases air pressure inside the lungs.
Sent 7: This action allows air and gases to enter the lungs.
Sent 8: Exhaling, or breathing out, occurs when the diaphragm muscle relaxes.
Sent 9: This decreases the size of the chest.
Sent 10: This increases air pressure inside the lungs.
Sent 11: This action allows for air to leave the lungs.
Sent 12: When you inhale, air enters the respiratory system through your nose and ends up in your lungs, where gas exchange with the blood takes place.
Sent 13: What happens to the air along the way?
Sent 14: In the nose, mucus and hairs trap any dust or other particles in the air.
Sent 15: The air is also warmed and moistened.
Sent 16: Next, air passes through a passageway that is connected to the windpipe.
Sent 17: The air then finds its way to the lungs.
Sent 18: In the chest, the windpipe splits so that air enters both the right and left lung. 
Question: What warms the air?.
Output:
Mucus and hairs.