Question

The central circular aperture of _______ is called ________
(A) iris, pupil
(B) pupil, iris
(C) retina, iris
(D) none

Answer 1

Hint: Looking at the options given it is clear here it is talking about the human eye. The human eye is a very delicate organ present in the human body and helps us in sensation of vision. It consists of many parts and each part has its own role to play.

Complete Step by step answer: Here human eye Is shown with its different parts labelled.

Now we can see in this figure that pupil is the black circle in the centre of the eye. So, the circular aperture through which light enters the eye is the pupil. The pupil is a black circle in the centre of the iris. So, the pupil lies inside the iris. Thus, the statement can be rephrased as: The central circular aperture of the iris is called the pupil.

Hence, the correct option is (A).

Additional Information: Iris plays a very important role in the functioning of the human eye. It regulates the amount of light entering our eye. When there is a bright light, the iris closes the pupil so that less light enters our eye and when there is low light, the iris opens up the pupil to let in more light into our eye.

Note: It is very confusing to look at the iris and pupil in the human eye diagram. Also, the accommodation of the lens is not done by iris or pupil but by ciliary muscles. We sometimes get confused but it is the ciliary muscles which enable the lens to change shape for focusing.