Question

What factor allowed the Incas to use their military efficiently?

they developed an extensive system of paved stone roads

they created a unique record-keeping system for military campaigns

they adopted Spanish military technology and used them against their enemies

they used rivers to transport their troops

Answer 1

I'd go with the first answer, that they developed an extensive system of paved stone roads. The entire empire was linked together with a massive network of trails and paved roads that connected everyone.

The record-keeping system they used was also important, but not so much when it came to moving military assets to where they would be needed most in comparison to having a good road system -- something important to any military campaign from the Romans to WW2. They certainly didn't adopt Spanish technology, and rivers were not as important as a transport option because of the mountainous region they lived in.

Answer 2

OKAY THANK YUH