The Cambrian Period is a time in the Earth's history when
A) the first abundant shelly organisms appeared in the fossil record.
B) the 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 appearance of the first abundant shelly organisms in the fossil record, marking the beginning of the Paleozoic Era. Options B and C are not relevant to the Cambrian Period, and option D is incorrect as dinosaurs did not appear until much later in the Mesozoic Era.

The Cambrian Period Is a Time in the Earth's History