WHY ARE IGLOOS ALWAYS ROUND IN SHAPE?

                                         The shape if the igloo is semi-circular because this shape can bear the impact of small objects hurled at it and the force of the sharp winds pressing on it. Don't you know that the sun, the moon, the earth and the stars are all spherical?
                                        Ice is a poor conductor of heat. Therefore, it is used to protect Eskimos from cold.

An Igloo

HOW DID OXYGEN ORIGINATE IN THE WORLD?

                When the earth was born about 4,600 million years ago, the atmosphere was mostly made up of hydrogen, ammonia, methane and water vapour. There was no oxygen. It took 600 million years for the first form of life to appear - simple, single-celled micro organisms. This was the only form of life for the next 2,000 million years. During this time, some of these early cells developed the ability to photosynthesize. This process, as you know, gives out oxygen as a waste product. In course of millions of years an oxygen-rich atmosphere was created which became the source of life for millions of animal species on earth.

HOW CAN ASTRONAUTS WALK IN SPACE???

                             The question arises in our mind because we are all accustomed to the gravitational pull of the earth. In space where gravitational pull is almost zero, it is easy to walk.

An Astronaut