Final answer:
The battles between Nomadic Steppe groups over grassland and water rights were primarily driven by scarce resources and territorial disputes.
Step-by-step explanation:
The frequent battles of grassland and water rights between Nomadic Steppe groups can be attributed to scarce resources leading to territorial disputes. Competition for limited resources like grasslands and water sources caused conflicts among the groups. As the arid climate and desertification impacted the availability of grass, nomadic pastoralists fought over the limited resources.