Question

please tell a short summary of the desert of class 7th ncert solution and please tell this question answer also....I will surely mark as brainlist answer....please tell fastly it's urgent ​its of English

Answer 1

Answer:

Explanation:

A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation. About one-third of the land surface of the world is arid or semi-arid. This includes much of the polar regions, where little precipitation occurs, and which are sometimes called polar deserts or "cold deserts". Deserts can be classified by the amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location.

Deserts are formed by weathering processes as large variations in temperature between day and night put strains on the rocks, which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter, and the resulting fragments and rubble strewn over the desert floor are further eroded by the wind. This picks up particles of sand and dust and wafts them aloft in sand or dust storms. Wind-blown sand grains striking any solid object in their path can abrade the surface. Rocks are smoothed down, and the wind sorts sand into uniform deposits. The grains end up as level sheets of sand or are piled high in billowing sand dunes. Other deserts are flat, stony plains where all the fine material has been blown away and the surface consists of a mosaic of smooth stones. These areas are known as desert pavements, and little further erosion takes place. Other desert features include rock outcrops, exposed bedrock and clays once deposited by flowing water. Temporary lakes may form and salt pans may be left when waters evaporate. There may be underground sources of water, in the form of springs and seepages from aquifers. Where these are found, oases can occur.

Plants and animals living in the desert need special adaptations to survive in the harsh environment. Plants tend to be tough and wiry with small or no leaves, water-resistant cuticles, and often spines to deter herbivory. Some annual plants germinate, bloom and die in the course of a few weeks after rainfall, while other long-lived plants survive for years and have deep root systems able to tap underground moisture. Animals need to keep cool and find enough food and water to survive. Many are nocturnal, and stay in the shade or underground during the heat of the day. They tend to be efficient at conserving water, extracting most of their needs from their food and concentrating their urine. Some animals remain in a state of dormancy for long periods, ready to become active again during the rare rainfall. They then reproduce rapidly while conditions are favorable before returning to dormancy.

People have struggled to live in deserts and the surrounding semi-arid lands for millennia. Nomads have moved their flocks and herds to wherever grazing is available, and oases have provided opportunities for a more settled way of life. The cultivation of semi-arid regions encourages erosion of soil and is one of the causes of increased desertification. Desert farming is possible with the aid of irrigation, and the Imperial Valley in California provides an example of how previously barren land can be made productive by the import of water from an outside source. Many trade routes have been forged across deserts, especially across the Sahara Desert, and traditionally were used by caravans of camels carrying salt, gold, ivory and other goods. Large numbers of slaves were also taken northwards across the Sahara[citation needed]. Some mineral extraction also takes place in deserts, and the uninterrupted sunlight gives potential for the capture of large quantities of solar energy.

Answer 2

Explanation:

The Desert Summary In English

Most people believe that the desert is an endless stretch of land. They thin. that it is dry, hot, waterless and without shelter. The specialists, however, see the desert as a beautiful place. For them a desert is the home of a variety of people, animals and plants.

True, that it does not always have a cover of grass. The rain is rare. But when it does, the desert becomes as beautiful as any tropical garden.

A desert may sometimes have mountains and hills. It may have an oasis also. A desert can be hot like the Thar or cold like Ladakh. In general, when a place has little or no water and vegetation, people call it a desert. Sand dunes are found in those deserts which are almost totally without water. These dunes keep on shifting across the desert.

All creatures need water. The animals and plants of the desert are able to survive on less water. A camel can do without water for days together. The reason is that a camel can drink a lot of water at one time. Now camels do not sweat, so they retain the water they drink for a long time.

Smaller desert animals get their water from the moisture in the things they eat. So some of them get the water they need from the animals they eat. Those who don’t eat meat, eat plants and seeds. Thus they get the needed water from plant juices.

In our cities and villages, the climate is humid. The moisture in the air acts like a blanket. It protects the earth from the hot rays of the sun. So the earth is not very hot during the day. The same cover doesn’t let the heat go out during the night. So the earth is not very cold during the night. Thus the variation in temperature during the 24 hours is not much. Since there is no such cover in the desert, there is much variation between the day and night temperature there. The temperature rises much during the day. In the same way, it falls much during the night.