What proof has been found that proves there was specialization of jobs?

Different working tools.

Explanation:

Many historians often debated whether ancient civilizations already understand the concept of job specialization. (where the people are divided into groups based on their expertise).

To proof Specializations of job exist in ancient civilizations, many historians pointed out to different varieties of tools that is found from their archeological sites. The tools were specifically designed to help the people with specific tasks that can only exist if there was specialization of jobs in that society.

answer; protectionism fosters competition and keeps price regulated;