How can art be a form of protest? Why was art a successful means for African Americans to challenge discrimination and offensive stereotypes during this time?

They could express their feelings.

Explanation:

They can express their feelings against discrimination through prices of art wether it be music, dance or drawing or any kind of art.

type of error:

the error in the sentence is a "dangling modifier". a dangling modifier is a phrase, word or clause that "dangles" because there is not target to modify. in this case, "after mopping the floor" is the dangling modifier since it has no word to modify. the noun "house" cannot mop the floor; therefore there is a mistake in the writing of the sentence.