Question

Colour of the eye like blue or black is due to

• A. Sclera
• B. Choroid
• C. Retina
• D. Iris

Answer 1

The correct option is D

Iris

The correct option is-D

The explanation for the correct option:

1. Iris is the pigmented circular diaphragm attached to the ciliary body in front of the lens of the eye.
2. It contains two types of muscles: circular muscles and radial muscles.
3. The pigment of the iris gives colour to the eye such as black, blue, green, brown, etc.

The explanation for the incorrect options:

Option-A

1. The sclera is the outer covering layer of the eyeball.
2. It is a comparatively tough, translucent (except at the region of the cornea), and thick layer.
3. It is composed of white collagenous connective tissue.

Option-B:

1. The choroid is the melanin-containing brownish layer.
2. It is present beneath the sclera.

Option-C

1. The innermost layer of the human eye is the retina.
2. This layer is made up of nervous tissue and connective tissue.
3. This layer is also known as a neural coat.
4. The retina contains two types of photosensitive cells-rod cells and cone cells.
5. Rod cells help us to see in dim light.
6. Cone cells help us to see in bright light and perceive colours.

Final answer: The colour of the human eye like blue or black is due to the colour of the iris.