natural resources
Explanation:
The conflicts that have emerged in the world, such as the two world wars and the cold war, have been primarily because of the right to exploit natural resources. The natural resources are what drives the economies, so they are crucial for developing, making profit, sustaining and developing their armies. In order to get hold onto the natural resources, the great powers often had to resort to military interventions, or rather invading some regions or territories, or at least putting them under their control. But the problem was that there were multiple competitors for those natural resources, and all of them wanted to get their hands on them, so in the race to get them, they often ended up in military conflicts.