The fact that most buildings in the Indus Valley were close in size has led archaeologists to believe that

the Harappan culture was not very advanced

the people of the Indus Valley worshiped only one god

the taller buildings were destroyed by natural disasters.

Indus society was relatively egalitarian

The fact that most buildings in the Indus Valley were close in size has led archaeologists to believe that Indus society was relatively egalitarian.

Explanation:

Indus Valley civilization is one the oldest to ever exist on the planet and has been remaining a mystery for the researchers for a long time.

It is believed that the Indus Valley Civilization was an egalitarian one as there were houses found in excavations that are similar to each other in many respects.

This happens in egalitarian societies where there is not much difference between the rich and the poor and it was certainly unusual for any society of that time to be like this.