Answer : 1. "Agriculture "
Explanation :

The economic base of Indus civilization was agriculture and animal husbandary cotton was first cultivated by the people of Indus civilization. In addition, they used to produce wheat, barley and rice, The Evidences of cow, ox, buffalo, camel, sheep, goot, pig, and dog etc. are found there. But Indus people didn’t know about horses. These people were expert in business and craft Industry.