Which of these was illustrated by both Harappa and Sumer? The influence of Mesoamericans The simultaneous development of cities and agriculture The close connection between river valleys and early civilizations The rapid (less than a century) rise and fall of a river valley civilization

## Step 1<br />The problem is asking us to identify a common characteristic between the Harappa and Sumer civilizations. Both of these civilizations were located in river valleys, which is a significant factor in their development.<br /><br />## Step 2<br />The Harappa civilization was located in the Indus River Valley, while the Sumer civilization was located in the Mesopotamian Valley, between the Tigris and Euphrates rivers. Both of these civilizations developed in fertile river valleys, which allowed them to establish agriculture and cities.<br /><br />## Step 3<br />The other options, such as the influence of Mesoamericans, the simultaneous development of cities and agriculture, and the rapid rise and fall of a river valley civilization, are not common characteristics of both Harappa and Sumer.