Question

How could shifts in the physical environment have caused major changes in early civilizations?

Answer 1

It could cause major changes because, for example, Egypt was a very wet place, the Egyptians wouldn't build their buildings out of mud bricks because they would erode super fast. So change in the physical environment could change the way civilizations built their buildings, grow their food, or the way they travel. 

Answer 2

Answer:

The shifts in the climate in the early civilization could have changed the structure of civilization by pushing them to rise and fall. Climate change, especially drought and heavy rainfall might have been partly responsible for destroying the crops, which would eventually rise to hunger and starvation.  Another reason could be the natural calamities like Earthquake and Volcanoes eruption might have destroyed the entire communities.