The Cambrian Period is a time in Earth history when ________.
A)the first abundant shelly organisms appeared in the fossil record
B)Earth's interior was so hot that a solid outer crust,if present,was likely being extensively remelted
C)stable continental interiors,termed cratons,first formed
D)the dinosaurs appeared and came to dominate large-scale terrestrial life

Question

Quizplus · Accepted Answer

The Cambrian Period is known for the sudden appearance and diversification of many shelly organisms in the fossil record. This was a time of rapid evolution and diversification of life forms, particularly in the oceans. Options B and C do not describe the Cambrian Period specifically, and option D is incorrect as dinosaurs did not appear until much later in Earth's history.

The Cambrian Period Is a Time in Earth History When