Answer:
They led to a great drop in Kush’s population.
Explanation:
In order to conducted the invasions, The Kush empire have to sacrifice a lot of men in the battlefield. Not all of these men were soldiers. Some of them were common workers (such as farmers or artisans) that were made to join the battle.
This led to a great drop in Kush's population. They managed to recover it over time during the peace period after the invasions, but it's overall made the kingdom become more vulnerable compared to the period before the invasions.
