Answer
They were unaware of iron, the horse, and script.
Explanation
In the Chalcolithic Age (4000 BC - 1500 BC), although humans learned the use of copper and stone, they were unaware of iron, the horse, and the art of writing.
Key Points
- > First use of copper
- > No knowledge of script or horse
- > High child mortality
Additional Information
"- 'Black and Red Ware' pottery was common in this age.\n- People made knives, axes, and fishing hooks using copper and alloys."