In each set of terms given below, there is an odd one and cannot be grouped in the same category to which the other three belong. Identify the odd term in each set and name the category to which the remaining three belong. Example: Ovary, Fallopian tube, Ureter, Uterus. Odd term: Ureter. Category: Parts of female reproductive system.
Malleus, Iris, Stapes, Incus.
Topic: Ear ossicles
Answer
Odd term: IRIS. Category of the others: EAR OSSICLES (the bones of the middle ear).
Malleus (hammer), incus (anvil) and stapes (stirrup) are the three EAR OSSICLES — the smallest bones in the body — lying in the MIDDLE EAR. They amplify vibrations and pass them from the eardrum to the oval window.
The IRIS is part of the EYE: the coloured muscular curtain in front of the lens that controls the size of the pupil and so the amount of light entering.
Learn the ossicles IN ORDER (malleus → incus → stapes), because papers ask for the first, the last or the middle one, and for the STAPES in particular as the bone that fits into the oval window.