They actually invaded idia because of their wealth the turks not only invaded but became rulers of India. They wanted to show the Indians of how powerful they were and they also invaded because of the rivalry between the Indian rulers which gave opportunities to the turks
-less attacks
-don't have to share food and water
-don't have to share other resources
-can have land
-less religious disagreements
-more time goes to farming and math and stuff like that and less to war-planning
A). Region's rich soil and long growing season, fostered the development of strong agricultural producing colonies.