The study of embryos and other early stages of development can in the classification of living things, past and present, by providing clues about the -
f common ancestry among vertebrate species
g rate of appearances of new terrestrial organisms
h prokaryotic species that are at risk for extinction
j barriers to mating among marine populations

Common ancestry among vertebrate species

Explanation:

According to biogenetic law, stages of embryological development of an organism recapitulates its evolutionary history. The shared characters are exhibited by early embryological stages of various species while the derived features appear in later stages. Hence, study of embryos and other early stages of development help in classification by establishing the evolutionary relationship among vertebrate species.

it's     c       this is a cell (b) with a nucleus (c) containing dna (a). the dna is organized into chromosomes (d). a section of the chromosome that codes for a trait is called a gene (e).

thinking it would be physical characteristics