What type of learning sometimes occurs after an extended period of thinking about a problem but little or no direct, systematic interaction with the environment?

Insight learning.

Explanation:

Insight learning is a process in which learning occurs by understanding the relationships and parts of the problem instead of trial and error. It tends to be when one thinks "I did it!".

It sometimes happens over a long period of thinking about a problem without much systematic interaction with the environment.

sumerians were polytheistic, meaning they believed in many different gods. so, the best answer is c.