Why do sociologists consider race a social construct

Why do sociologists consider race a social construct? In your own opinion, explain how racial categorizations are used in social settings (when you meet someone for the first time) and by institutions (school, legal forms etc). Judging people by their race comes in many forms.

This can be from looks or if you haven't met someone in person, from their names. Conduct an online research and analyze some of the industries that are dominated by certain groups of people. Why do you think these patterns have emerged? Provide either a historical, economic, and political explanation.