Answer:
Since neither reptile could have swum great distances across salt water he inferred that they once lived on a single landmass that has since split apart.
Population distribution and density patterns can be useful to understand because they help to explain how and why people migrate and develop in certain places around the world. These factors influence human migration and development and are therefore important to understand if you seek to understand how the world has developed over time and what are the forces that are driving this development.