How could shifts in the physical environment have caused major changes in early civilizations? Select all that apply.

Buildup of silt could have made rivers less salty, increasing the supply of clean water.

Long-term farming could have improved the quality of the soil, increasing crop yields.

Too much or too little rain may have ruined crops, creating food shortages.

Earthquakes or erupting volcanoes may have destroyed communities.

The correct answers are C) Too much or too little rain may have ruined crops, creating food shortages and D) Earthquakes or erupting volcanoes may have destroyed communities.

Shifts in the physical environment could have caused major changes in early civilizations in the following ways: Too much or too little rain may have ruined crops, creating food shortages and earthquakes or erupting volcanoes may have destroyed communities.

We are talking about major changes. Not ordinary or common changes in the environment. Early civilizations settled in strategic places such as next to the rivers for the many benefits it represented. Let's set the example of the oldest human civilization known to man: the Sumerians. They established in the middle of the Rivers Tigris and Euphrates, in the Middle East region of what today is Iraq. They founded great city-states such as Lagash, Kish, Ur, or Uruk. They prospered but also were affected by major environmental changes such as earthquakes and flooding. Indeed, those civilizations disappeared during the las Great Deluge or flooding.

Too much or too little rain may have ruined crops creating food shortages and earthquakes or erupting volcano's may have destroyed communities