Question

What is wrong with this sentence "To attract customers, merchants occasionally pose live models next to mannequins they can't talk, smile, twitch or move a muscle.

Answer 1

It's a run on sentence

Answer 2

I think what is wrong is a punctuation mark.

To attract customers, merchants occasionally pose live models nest to mannequins. They can't talk, smile, twitch,or move a muscle.

hope I helped !