Question

Q 9) Read the extract and write its summary.

When you are deprived of sleep, your eyes don’t work as well, and difficulties with

vision are very common. The first changes are usually minor : some blurring of vision

when reading, or some errors in judging distance or depth. You may reach for a coffee

cup and miss because your eyes told you it was closer. As the period without sleep

lengthens, other visual errors become more common. Though a significant number of

normal people who undergo extended periods of wakefulness have hallucinations, it

usually takes a prolonged sleep loss – at least seventy-two hours – to bring these on.

During sleep loss of shorter duration, visual errors, mistakes in vision, are much more

common. Perhaps you “saw” the doorknob on the left rather than the right, or misread

the hands on the clock. These errors don’t happen if you focus your mind specifically

on the doorknob, for example, but if you are looking at something else and glimpse

the door out of the corner of your eye, your perception of the knob’s location may very

well be wrong if you are very sleepy. These errors are easily corrected, and often

comical, but they do show that the visual system, one of the most important for

information gathering, is not working well. Similarly, it’s quite common to have some

difficulty with coordination, and mild hand tremor or difficulty with fine motor skills (such

as threading a needle) often occurs.​

Answer 1

This is cuboidal in shape and forms the lining of kidney tubules and ducts of salivaiy glands.

In some cases a portion of the epithelial tissue folds inward to form a multicellular gland. This is called glandular epithelium.

It performs a function of secretion and absorption.