1
Gas which found a lot in expiration
2
Branches of trachea
3
The trachea contain ..... which removes dust, dirt and bacteria from the air.
4
Part of lungs where gas exchange occurs
5
The process of breathing when the diaphragm contract and flatten
6
Parts of respiration that prevent food enter the trachea and lungs
7
The windpipe which contain C-shaped rings of cartilage
