The Cambrian Period was the first geological period of the Paleozoic Era, which of the following characterizes the Cambrian period? Choose the correct answer. a
dinosaurs flourished, all life lived in the sea and humans appeared
b
invertebrates developed, all life lived in the sea, and ocean organisms with shells and outer skeletons developed
c
single-celled life, humans appeared, and dinosaurs flourished
d
dinosaurs flourished, multi-celled life appeared, and all life lived on land