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which is a difference between the paleozoic and mesozoic era?

a. animals lived in the water during the mesozoic and on land in the paleozoic.
b. the first birds emerged in the paleozoic era while mammals first emerged in the mesozoic.
c. many different species of dinosaurs lived in the mesozoic, but they all died off in the paleozoic.
d. animal complexity increased during the paleozoic while the first flowering plants appeared in the mesozoic era.

Cladistics is a way of classifying organisms by examining the characteristics of their ancestors and descendants and depicting the relationships in a cladogram. which of the following best describes a challenge in classifying organisms this way? a. there are millions of species on earth, and a cladogram is not a practical means for classifying all of them. b. it is impossible to tell which organisms are most closely related to each other using a cladogram. c. cladograms are detail-oriented and do not provide a useful understanding of evolutionary relationships. d. there is a limited number of ways to organize the information, so most cladograms end up looking very similar.