Air is not a hetrogenous mixture. Hetrogenous means you can see what is in it. Not only can't you see wats in air you can't even see air itself! So, air is homogenous!!!
Air is a heterogeneous mixture.
75% nitrogen and 25% oxygen
The hair shaft is made up of dead, hard protein called keratin in three layers. The inner layer is called the medulla and may not be present. The next layer is the cortex and the outer layer is the cuticle. The cortex makes up the majority of the hair shaft. The cuticle is formed by tightly packed scales in an overlapping structure similar to roof shingles. Most hair conditioning products attempt to affect the cuticle. There are pigment cells that are distributed throughout the cortex and medulla giving the hair it's characteristic color.
Mainly air is made of Nitrogen and Oxygen...there is about 1% trace of other elements.