Commerce (English Medium) कक्षा ११ - CBSE Question Bank Solutions for English Core

Read the text below and summarise it.

The Great Desert Where Hippos Once Wallowed

The Sahara sets a standard for dry land. It’s the world’s largest desert. Relative humidity can drop into the low single digits. There are places where it rains only about once a century. There are people who reach the end of their lives without ever seeing water come from the sky.

Yet beneath the Sahara are vast aquifers of fresh water, enough liquid to fill a small sea. It is fossil water, a treasure laid down in prehistoric times, some of it possibly a million years old. Just 6,000 years ago, the Sahara was a much different place.

It was green. Prehistoric rock art in the Sahara shows something surprising: hippopotamuses, which need year-round water.

“We don’t have much evidence of a tropical paradise out there, but we had something perfectly liveable,” says Jennifer Smith, a geologist at Washington University in St Louis.

The green Sahara was the product of the migration of the paleo-monsoon. In the same way that ice ages come and go, so too do monsoons migrate north and south. The dynamics of earth’s motion are responsible. The tilt of the earth’s axis varies in a regular cycle — sometimes the planet is more tilted towards the sun, sometimes less so. The axis also wobbles like a spinning top. The date of the earth’s perihelion — its closest approach to the sun — varies in cycle as well.

At times when the Northern Hemisphere tilts sharply towards the sun and the planet makes its closest approach, the increased blast of sunlight during the north’s summer months can cause the African monsoon (which currently occurs between the Equator and roughly 17°N latitude) to shift to the north as it did 10,000 years ago, inundating North Africa.

Around 5,000 years ago the monsoon shifted dramatically southward again. The prehistoric inhabitants of the Sahara discovered that their relatively green surroundings were undergoing something worse than a drought (and perhaps they migrated towards the Nile Valley, where Egyptian culture began to flourish at around the same time).

“We’re learning, and only in recent years, that some climate changes in the past have been as rapid as anything underway today,” says Robert Giegengack, a University of Pennsylvania geologist.

As the land dried out and vegetation decreased, the soil lost its ability to hold water when it did rain. Fewer clouds formed from evaporation. When it rained, the water washed away and evaporated quickly. There was a kind of runaway drying effect. By 4,000 years ago the Sahara had become what it is today.

No one knows how human-driven climate change may alter the Sahara in the future. It’s something scientists can ponder while sipping bottled fossil water pumped from underground.

“It’s the best water in Egypt,” Giegengack said — clean, refreshing mineral water. If you want to drink something good, try the ancient buried treasure of the Sahara.

Notice the italicized sentence placed at the top of the article which tells us at a glance what the article is about.

Divide the article into four sections based on the shifts in the sub-topics and give a suitable sub-heading for each section. One has been done for you in the article as an example.

Look for pictures in newspapers and magazines that depict the urban civic problems discussed in the text. Cut them out and pin them to the text at appropriate places.

Put down the images that come to your mind immediately when you see the words in the box.

Look for a story, a poem and a newspaper article on environment conservation and see how the style of each is different from the other.

Notice these expressions in the text. Infer their meaning from the context.

• blow-by-blow account

• morale booster

• relegated to

• political acumen

• de facto

• astute

• doctored accounts

• gave vent to

Tick the statement that is true.

The story is an account of real events.

Tick the statement that is true.

The story hinges on a particular historical event.

Tick the statement that is true.

Rajendra Desphande was a historical event.

Tick the statement that is true.

The places mentioned in the story are all imaginary.

Tick the statement that is true.

The story tries to relate history to Science.

Briefly explain the following statement from the text.

Briefly explain the following statement from the text.

Briefly explain the following statement from the text.

Briefly explain the following statement from the text.

Briefly explain the following statement from the text.

Discuss the following statement in groups of two pairs, each pair in a group taking opposite points of view.

Discuss the following statement in groups of two pairs, each pair in a group taking opposite points of view.

Discuss the following statement in groups of two pairs, each pair in a group taking opposite points of view.