How can independent assortment explain genetic diversity in humans?

Independent assortment allows parent gametes to create a unique combination of characters in the offspring and recombine with another set of genes. If independent assortment does not occur, most likely the offsprings will inherit the characteristics of the parent gametes. They will remain as is. 

It keeps pressure in plants, it also holds structure whilst growing. In both animals and plants, they store nutrients. Thats all I got XD