A. Answer these questions briefly.
1. How is the distance between the Earth and the Sun favourable to the Earth?
2. What are the unique features of the Earth?
3. Mention three features of the Earth that make it suitable for life.
4. Why is the atmosphere of the Earth unique in the Solar System?
5. Mention the importance of the lithosphere.
6. What is antipodal balance?
Answers
Explanation:
How can you prove that the earth is a sphere by looking at the Pole Star ?
Answer:
The Pole Star can be seen at an angle of 90° at the North Pole, as it lies directly at the line of axis of the earth, while its angle decreases towards the Equator i.e. it is 0° at the equator. It is only possible in an quarter arc of a circle. It proves that the earth is a sphere with circular surface.
Question 2.
Briefly describe the shape of the earth.
Answer:
The earth has got a spherical shape, slightly bulging at the equator and flattened at the poles. The spherical shape is confirmed by the arrival of a ship seen first by its mast and later on the ship. The satellite picture of the earth, shadow of the earth on the moon as circular, and the views of circular horizons from the height etc. all these prove the spherical shape of the earth.
Question 3.
What is the earth’s mean temperature ? State its one advantage.
Answer:
The earth’s mean temperature is 17° C, which is ideal to support the survival of the life-system.
Question 4.
Why is the earth called a watery planet ?
Answer:
The earth is called a watery planet, as its major part i.e. 70% is covered by water or hydrosphere. The earth is seen blue in the satellite pictures due to the majority of water.
Question 5.
What is ‘biosphere’ ?
Answer:
Biosphere is the narrow zone of contact amidst lithosphere, hydrosphere and atmosphere.
Question 6.
Name the conditions necessary for life on earth.
Answer:
The conditions necessary for life on earth, are ideal temperature range with an average between 10°C and 35°C, solar radiation, humidity, wind, water, land etc.
Answer:
1) The distance between earth and Sun is useful because in this zone the water remains in liquid form which supports life. This zone is called goldilocks zone.
2)Three unique features of earth are:
It is located at an optimum distance from the Sun. Hence, it is neither too cold nor too hot. ...
The earth is a watery planet with 70% of the earth's surface covered by water.
It has an atmosphere which receives heat from the sun by solar radiation and loses heat by earth's radiation.
3)Distance of the Earth from the Sun.
Importance of light on the Earth.
Importance of Earth's Atmosphere.
Importance of Ozone Layer.
Favourable Climatic Condition.
Water.Force of attraction (Earth's gravitational pull)
4)Earth is special because it is an ocean planet. Water covers 70 percent of Earth's surface. Earth's atmosphere is made mostly of nitrogen and has plenty of oxygen for us to breathe. The atmosphere also protects us from incoming meteoroids, most of which break up before they can hit the surface.
5)Lithosphere provide us forests, grasslands for grazing land for agriculture and human settlements and also rich source of minerals. The lithosphere contains different types of rocks such as the igneous, sedimentary and metamorphic rocks, it helps to provide the necessary nutrients required to plants.
6)There is an antipodal balance of land and water on directly opposite sides of the globe. It means that the continents and oceans are roughly arranged in such a way that land on one side of the globe is balanced by water on the opposite side of the globe.