Question

multiple choice question. the start of the phanerozoic eon about 543 million years ago marks the time when become abundant due to the evolution of certain types of body forms. dinosaurs humans marsupial mammals animal fossils. need help? review these concept resources.

Explanation:

At the start of the Phanerozoic eon about 543 million years ago, animal fossils became abundant as they evolved various body forms.

Answer:

animal fossils