Why didn't the Inca have protection from Smallpox?

What are the reasons that some europeans moved and began colonizing the new world? select all that apply: options: better economic opportunities. some were escaping religious persecution. attempting to increase their wealth, despite the hardships and risks. the new world was safer and more secure than the old world.

Which physical feature minimizes population density in northern africa?

Why did einstein write a letter to president roosevelt