Teacher:In this task, you are given a paragraph, event and an entity. The event is part of the given paragraph and it changes the state of the entity. Your task is to classify the state of the entity into three classes: 1) not exist, 2) unknown location and 3) known location. "not exist" means the entity doesn't exist in that state anymore. "unknown location" means the entity exists in that state but location is unknown. "known location" means the entity exists and location is known. 
Teacher: Now, understand the problem? Solve this instance:  "process paragraph : : Sound waves enter your outer ear. Travel through ear canal to your ear drum. Eardrum vibrates with the incoming sound. Send the vibrations to three tiny bones in your middle ear. Bones in your middle ear amplify the vibrations. Send them to your inner ear. The vibrations activate tiny hair cells in your inner ear. The hair cells release neurochemical messengers. Your auditory nerve carries the message to your brain. The brain translates the message so you can understand. ", "event : Travel through ear canal to your ear drum.", "entity : neurochemical messengers" 
Student:
 unknown location 