Is the sentence in ( bold) a main idea or a detail? Read the picture to answer the question. Will Mark Brainliest and only answer if your 100% correct please.

Answer:
Detail
Explanation:
The bolded sentence is a detail that adds to the main idea, which is the first sentence:
The coming of Spaniards to South America brought disaster to Native Americans.
The fact that the invaders killed thousands and destroyed cities adds to why there was disaster to Native Americans.
I hope this helps!