It is important for a food business to keep out flying insects. screens on kitchen doors can be very effevtive as long as the screen mesh is the right size, there are no tears and

check for the pregnancy rating of drug. if its class c or d see if other alternatives

air enters through the nose, moves through the nasal cavity, the pharynx, the larynx, enters the trachea, moves through the bronchi andbronchioles till the alveoli.