The principle of common descent helps explain why

DNA and bone structure

Explanation:

the dna helps alot to know what happened and what are the descendants of this animal.bc the animals that were like really close and well it easy to find out

the answer is c-birds and reptiles share a number of inherited characteristics.

Explanation:

answer; polycythemia is the correct answer;

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".