The first inventions that harness natural energy resource is Water mill. Back then, people use the power of water to move the lever in order to create mechanical movement.
The invention that help transfer water from river to town is aqueduct. Or more commonly knwon as water bridgte, useful to navigate the movement of water.
Lever is the invention that makes lifting weight easier, mostly used in contruction sites.
Answer:
They were used to cause terror in the enemy and charge them to break their ranks
Explanation: