Biology [2 Mark Question Answer]

1 - vitreous humour,
2 - Fovea centralis (yellow spot),
3-lens,
4-pupil

(1) Static balance - Utriculus and sacculus (inner ear)
(2) Hearing - Internal ear
(3) Dynamic balance - Semi-circular canals (inner ear)

An optical illusion is the life-like continuous movement on the screen. Television is an example of optical illusion, where the scanning beam of a picture frame of the TV camera moves so rapidly on the viewing screen of the TV set that our eyes cannot keep pace with it.

Presbyopia is an age-old eye defect. In this condition, the lens loses flexibility resulting in far-sightedness.
Cataract is also very common in old people, the cornea becomes opaque and the vision is cut down even to blindness.

Presbyopia is an age-old eye defect. In this condition, the lens loses flexibility resulting in far-sightedness.
Cataract is also very common in old people, the cornea becomes opaque and the vision is cut down even to blindness.

cochlea is responsible for hearing; it can perceive the senses of hearing.
Semicircular canals are responsible for perceiving the senses to maintain the body balance.

Rods are sensitive to dim light but do not respond to colour.
cones are sensitive to bright light and are responsible for colour vision.

Myopia results when the eye ball is lengthened from front to back or the lens is too curved.
Hyperopia results from either too shortening of the eyeball from front to back or when the lens is too flat.

The three ear ossicles are: Malleus (hammer), Incus (anvil), and Stapes (stirrup).
The last ear ossicle, stapes, vibrates and transmits the vibration to the oval window. The role of the other two ear ossicles is to magnify the vibration of stapes as a result of their lever like action.

Our eyes are designed to focus at a great variety of distances. To focus constantly at a short distance can make the lens focusing muscles fatigued. Therefore, we do not enjoy watching a movie from a very short distance from the screen in cinema hall.

If we look at a bright object and then close our eyes, the sensation of light persists for a short period. This is known as persistence image or the after image. It lasts for one-tenth of a second. Therefore by closing the eyes and gently pressing them with your palms, you see some specs of brilliant light.