ii)1. It gives the lungs a large surface area to volume ratio.
2. It is moist and thin.
b) P has a disc or biconcave shape which allows the O2 to bind to it with the help of a protein called haemoglobin for it to be transferred to various parts of the body.
c) Carbon monoxide will bind to the haemoglobin to form carboxyhaemoglobin causing oxygen disruption
