Answer:
The subject the explosion of clown crews and the predicate/verb allow are not in agreement because the subject is in the singular form, and the predicate in the plural. This is the correct way to rewrite the sentence:
The explosion of clown crews allows unique styles of dance to evolve, such as krumping. OR
The explosions of clown crews allow unique styles of dance to evolve, such as krumping.
Step-by-step explanation: