Question

______ can relax and contract , there by adjusting the size of an aperture.
A) Iris
B) Pupil
C) Yellow spot
D) Blind spot ​

Answer 1

Answer:

pupil is the answer of the question

Answer 2

Iris can relax and contract, thereby adjusting the size of an aperture.

Aperture is the Opening in a Lens through which light enters.

In Human Eye, Pupil acts as Aperture.

Some Terms of Human Eye and their Explanations -

1. Yellow spot is a spot by the side of the Eye ball or Iris where maximum cone cells are present. High resolution, colour images are formed here. It is the most sensitive part of eye where sharpest image is formed.
2. Retina is the Screen on which Image of object is formed. Retina has a tiny hole through which the Optic nerve passes and goes to the Brain. This tiny hole area has no Photo-receptors. So, It can't sense light and frame an image. When Light rays from an object, entering the eye converge at this point of the Retina, then, that person cannot see the object. This is called Blind Spot.
3. Cornea is the thin transparent white membrane covering the surface of the eyeball. It acts as a Primary lens through which Light enters into the eye. Maximum Refraction of Light takes place here.
4. Iris is the dark muscular diaphragm just behind Cornea. It controls the size of Pupil and gives colour to the eye. You might have seen persons with black eyes, brown eyes, green eyes, blue eyes, etc. Iris gives colour to the Eye.
5. Pupil is the small dark hole in the middle of the eye or Iris. It controls the amount of Light entering into the Eye.

• In Dim Light → Pupil expands completely due to Relaxation of Iris muscles.
• In Bright Light → Pupil contracts due to contraction of Iris muscles.