You might be interested in these responses from the FAQ:

The native americans and several other cultures did not experience the same technological advancements as europe. What has caused this diffrence? [user unfortunately deleted]

Why weren't civilizations in the ancient north America's more advanced? by /u/RioAbajo

Why were Native American civilizations so far behind their counterparts throughout the world? by /u/The_Alaskan

When Europeans brought diseases to the new world, how come Europeans themselves didn't get sick from diseases specific to the new world? by /u/anthropology_nerd

If these leave you with further questions, feel free to ask!