I Think The answer is b I hope it helps ya
Answer:
<u><em>River valley civilizations</em></u>
Explanation:
They were centred around various river valleys as their main source of livelihood and the flourished only due tiote river valley on which they were based. Like the harappan in Indus Valley, The yellow river (Huang He), the Mesopotamia around Tigris and Euphrates and the egyptian Nile.
Human beings are born into an environment that is [different] ? to us in many ways
how a mineral reflects light from its surface is known as: luster