ANCIENT GREECE describes the time from around 1500BC to about 200 years after the birth of Christ .The Greek civilization is known for its great philosophers ,scientists ,and democracy .Greek had a common language and worshiped a common God Zeus..But their king was not common king .There were many city states like Sparta and Athens which fought among themselves. The Greek established trade centers all around the Mediterranean Sea.They were the competitors of the Phoenicians ,who settle down in North America.City states with powerful castles arose on the Greek mainland .At around 1200 BC ,warring races from the North east conquered one of the powerful city-states .But around 800BC City -states once again become powerful. City -states were governed by noble,known as polish ,were allowed to to decide on matters
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IN ,1991 ,A project was started in USA to study the complete genetic material of humans.The genetic material also called 'genome' ,contains the information necessary for the development and the characteristics of a living organism .This information is present in the DNA which is a chemical compound , that looks like twisted rope ladder .In this project ,researchers wanted to find out about the individual components of the ladder .This was not at all easy because there was billions of components .Today almost all of them have been studied .The 'decoding' of the genetic material promises , a better understanding of and a cure for hereditary diseases. HUMAN GENETIC MATERIAL
SPACE SUITS are wear by the Astronauts who go into space.It protects them .Earlier Astronauts had only one type of space suits,but today they wear different type of space suits for different activities.For working in a space station there is a light weight space suite,a special space suit for to and fro flight .For walking outside the spaceship ,air sealed space suit is used.The space suit for walking in the space comprise many many layers of plastic and textiles .Coolants run through the tubes in the inner most layer,which protect the astronauts against over heating during strenuous work.A middle layer maintains the inside pressure against the extreme low pressure of the empty space.Space suits are very important with out the space suit the air would escape from the lungs of the astronauts , and the body cell would burst
MONEY IS A Medium of exchange of a certain value,which one can not consume or utilize directly..Thousands of years ago people exchanged useful items with one another .Later ,objects used for exchange ,which had a generally known value,were used as a mode the mode of payment.But, when requirement of exchange increased ,the first coin were made ,later followed by paper money.Banks took over the money business.They lent money or printed notes ,during a inflation. THE EARLIER MONEY .-Earlier people paid with different things such as ,stones,shells,rings, piece of iron, or salt.In Africa cowries were used as a means of payment .In north America , payments was made with salt.These were easy to store, count and transport.Sometimes silver and bronze were used in the form of bars. USES OF COINS - COINS were used as a mean
OUR ENVIRONMENT IS IN DANGER.Man made Catastrophe ,for which human being are responsible .Man made disasters pollute huge areas and cause extensive damage to animals ,plants, and even to human beings.like ,Oil and chemical spills,accidents in nuclear power plants ,over fishing in seas. and large scales destruction of forests.Besides, increased green house effect .all are man made environmental catastrophe. OIL AND CHEMICAL SPILLS .-Chemical accidents are caused by human negligence,technical problems, and are committed by the people employed in the chemical factories or in the transportation of chemicals.The example of this ,took place in Bhopal the capital city of MAHDYA PRADESH in 1984,where poisonous gas leaked from a chemical factory killing 3000,people . Oil spill takes place in seas ,when oil tankers accidentally overturned in water.Then it pours
NATURAL RESOURCES are derived from the environment and are essential for our survival .These include crude oil, coal, natural gas, which gives energy.The resources are found in the Earth's crust like metal ores,salt, lime, quartz sand, precious stones.Besides drinking water,soil,forests are also natural resources.All these resources are needed for our day to day life, and our very existence . Some of the most important resources are -ORES. ORES -METALS occur in the form of ORES.They are mixed with rocks They are extracted from the ore by the process of Smelting .Metal is melted out of the rocks.Iron is extracted from iron ore .Smelting is done in huge furnaces . in steel plants..Metals are used mainly in the form of alloys , which is a mixture of two metals.like ,Iron is changed into steel by adding Carbon The amoun
THERE ARE MANY KINDS OF DESERTS IN THE WORLD-Such as snow deserts, water deserts and sandy or dry deserts.In Sandy or dry desert there are vast tracts of sand with very high temperature and difference between day and night temperature..There are sand storms that blows hard and make life dangerous.Sand dunes are ever changing their shapes and places by the work of winds. Animals and plants adapt themselves to be able to survive in this harsh environment.Some animals like antelopes have developed tricks so that they are able to withstand thirst. PLANTS CACTUS - CACTI OR CACTUS have an outer waxy layer and their leaves have evolved into thorns to prevent evaporation of water.In the morning their thorns and outer waxy layer able to absorb dew drops .They store water water in their bodies and roots and use it slowly.