Chapter 21, Problem 20WIO

Summary Introduction

To determine:

Whether the fossil is of a mammal or a reptile by contrasting their characteristic features.

Concept Introduction:

Mammals and reptiles both belong from the class chordates. The fossils of mammal and reptile are identified by bone shells, exoskeleton, stone imprints and DNA residue. A fossil represents the traces and remains of an animal or plants that have been preserved in rock for longer time. Mammals and reptiles have different body structure and arrangement of the bones and skeleton which helps in determining the fossils.