The biological basis for assigning all human beings into a singe species is that there so many, even tons of living organisms living on earth. These organisms differ in their external and internal organs and so to differentiate them from them, they are being classified into kingdoms then classes then phylums then family.
D. the moveable and proximal attachment
<span>When an athlete is nearing the end of a race and her cells are low on oxygen, it is likely to be fermentation. When cells have used up all their oxygen they ferment glucose into lactic acid. Fermentation is a metabolic process that consumes sugar in the absence of oxygen</span>
A camel's hump is an example of structural adaption.