21. the of animals is based on scientists’ current understanding of the evolutionary history of living species. (1 point)

The given blank can be filled with cladogram.

Explanation:

A cladogram refers to a diagram utilized by the researchers to demonstrate a phylogeny, which is considered as a hypothetical association between the groups of animals. It demonstrates groups of organisms, that is, how they are interrelated and associated with their common ancestors.  

Thus, the cladogram of animals is dependent upon scientists’ present understanding of the evolutionary history of living species.  

a=c and then d= c because of the band so you get ac/dc and you add them together you get sound waves

if you add everything up correctly you should get 69 i got this because 50 plus 19 is it