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. possible errors

d. new questions

explanation:

predictions and planning happen before. a summery comes after. errors you get after investigation and new questions propose what you can look for in the future.

blue stars have the highest surface temp

stellar distances are usually expressed in light-years

the measure of a star's brightness is called magnitude

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