Answer:
Kidneys
Explanation:
The paired kidneys are often considered the main organs of excretion. The primary function of the kidneys is the elimination of excess water and wastes from the bloodstream by the production of the liquid waste known as urine
Mutualism- in which two different organisms interact, and each organism benefits each other (think "positive, positive"; or " +,+ ").
An example would be Oxpeckers and zebras or rhinos - In this relationship, the oxpecker (a bird) lives on the zebra or rhino, sustaining itself by eating all of the bugs and parasites on the animal.
The bird benefits by having a readily available source of food.
The zebra or rhino benefits from having the bugs removed. Also, when there is a danger to the zebra or the rhino, the oxpecker flies high and makes much noise in order to alert nearby animals to the impending danger (i.e. a predator).
Read more at http://examples.yourdictionary.com/mutualism-examples.html#3LtWEwmHBJ53KFbb.99
In the ear, the sound waves enter through the auditory canal and hit the eardrum (tympanic membrane). The eardrum amplifies the sound and the waves move on to the middle ear, where three bones called the ossicles (malleus, incus, and stapes) amplify the sound further and vibrate. Then, the sound waves go to the cochlea where tiny hairs and other receptors turn the sound waves into a nerve impulse. This impulse is sent to the brain via the auditory nerve and interpreted by the brain.
