WORLD CIVILIZATION

Detailed explanation-1: -The Sumerians, using their finger-joints to count the duodecimal (12) system, divided the day, sunrise to sunset, into 12 parts, so the combined day and night was divided into 24 parts. About 3500 years ago the Egyptian civilisation became the dominant civilisation and they embraced the duodecimal system (base 12).

Detailed explanation-2: -The Sumerians used a numerical system based on 1, 10 and 60. The way of writing a number like 70 would be the sign for 60 and the sign for 10 right after. This way of counting is still used today for measuring time as 60 seconds per minute and 60 minutes per hour.