Earth: Spheres, Structure and Measurements

The solid portion of the earth is called the Lithosphere. It comprises the rocks of the earth’s crust and the thin layers of soil that contain nutrient elements which sustain organisms.

North America is the third largest continent of the world. It is linked to South America by a very narrow strip of land called the Isthmus of Panama.

Biosphere,

71% of the surface of the earth is covered by water. The ocean and the seas covering largest surface area of the globe are of paramount significant to all of the living organism including man of the biosphere because they help in functioning of global hydrological cycle through atmospheric- oceanic circulation system. It absorbs carbon dioxide and thus help in reducing green house effect caused by human activities. It also help in the dispersal of seeds and small animals through ocean currents. 

There are 5 oceans in the world which covers about 70% of the total earth surface.These five oceans are namely, Pacific Ocean, Atlantic Ocean, Indian Ocean, Arctic Ocean and Antarctic ocean. Pacific Ocean is the largest ocean in the world on the other hand Arctic Ocean is the smallest ocean.

The lithosphere is the solid, outer part of the Earth. The lithosphere includes the brittle upper portion of the mantle and the crust, the outermost layers of Earth's structure. It is bounded by the atmosphere above and the asthenosphere below.

Due to the Earth's rotation, it is an oblate spheroid, meaning it bulges at the equator and is slightly flattened at the North and South poles.

Water covers  71 percent of the total surface area of the earth.

The biosphere is the global sum of all ecosystems, representing the zone of life on Earth, including all living organisms.

About 71%71% of the earth's surface is covered by water which has blue colour. Therefore the earth looks blue when viewed from the space.
The grains of the Martian soil appear to be coated with iron oxide rust and this planet appears to be red. Also the atmosphere here is filled with dust which gives a strong red colour to this planet. Hence Mars is often called the red plant.
Saturn has well established rings and Neptune has satellite but no rings.

• Dachigam National Park is located 22 kilometers from Srinagar, Jammu and Kashmir. It covers an area of 500 km². The name of the park literally stands for "ten villages" which could be in memory of the ten villages that were relocated for its formation
• Khangchendzonga National Park also Kanchenjunga Biosphere Reserve is a National Park and a Biosphere reserve located in Sikkim, India
• The Nanda Devi National Park or Nanda Devi Biosphere Reserve, established in 1982, is situated around the peak of Nanda Devi in the state of Uttarakhand in Northern India
• The Sundarbans is a mangrove area in the delta formed by the confluence of Ganges, Brahmaputra and Meghna Rivers in the Bay of Bengal.

• The air near the surface consists of nitrogen- 78% and oxygen- 20.9%.
• Thus option A is correct.
• Carbon Dioxide is found in very low quantities i.e. 0.003% hence incorrect.

• During the middle of the 19th century, Africa was referred to as the "Dark Continent," because little was known about the mysterious land itself.
  
•  The term "Dark Continent" was most likely used for the first time by United States explorer and journalist Henry Stanley.
  
•  The reason was that very little was known about Africa - other that its external borders until the Scramble for Africa. Livingstone and other explorers in the middle to late 19th Century "discovered" and mapped internal Africa.
  

• The highest active volcano in the world is Ojos del Salado on the Chile-Argentina border in the Central Andes. It rises to 6887 m / 22,595 ft. It has not erupted in historic times, but is an active volcano.
  

• Equatorial radius of the earth = 6378 km
• Polar radius of the earth = 6356 km
• Thus the nearest option is 6371 km . B is the correct option.

• The earth is not a complete sphere as it is a little flat at poles and bulges at the equator which makes its equatorial diameter greater than its polar diameter.
• The equatorial diameter of the Earth is 40075 km.

• The principle factor deciding the temperature of any place on Earth is the angle of sun rays falling upon the surface of the earth. Vertical rays i.e. rays inclined towards the surface bring in more insolation thus earth gets warmer. On the other hand, when the sun rays are inclined away from the earth's surface i.e. slanting rays,  brings in less insolation and thus temperature remains cooler. Thus B is correct.
• Option A is wrong as the distance from the sun does not contribute significantly towards the variation in temperature on earth.
• Option C is wrong as evaporation occurs in all the seasons.
• Option D is wrongly stated.

• New York City is situated in the banks of river The Hudson.
  
• The Hudson River is a 315-mile (507 km) river that flows from north to south primarily through eastern New York in the United States.
  
• The river originates in the Adirondack Mountains of Upstate New York, flows through the Hudson Valley, and eventually drains into the Atlantic Ocean, between New York City and jersey city.
  
• The river enters the Hudson Valley, flowing along the west bank of Albany and the east bank of Rensselaer.
  

The total surface area of the Earth is approximately 510 million square kilometers.

• The water hemisphere has only one-eighth of the world's land, Australia, New Zealand, Antarctica, a small part of Southeast Asia and the southern part of South America are in the water hemisphere.
•  Most of the Pacific Ocean and the Indian Ocean is on the water hemisphere.
• Southern Hemisphere climates tend to be slightly milder than those at similar latitudes in the Northern Hemisphere, except in the Antarctic which is colder than the Arctic.
• This is because the Southern Hemisphere has significantly more ocean and much less land; water heats up and cools down more slowly than land.

The lithosphere is the rigid, outermost shell of the Earth, consisting of the crust and the upper mantle.

The
biosphere is the layer of the planet Earth where life exists. This layer ranges
from heights of up to ten kilometres above sea level. It is the fourth component
of the earth. Biosphere is a life-supporting global ecosystem, where each
living things depends on each other and the environment. The biosphere extends
over the Earth's surface in a thin layer from a few kilometers into the
atmosphere, in very cold environments, to the deep-sea vents of the ocean
depths, in very hot environments.

The equatorial diameter of the Earth is approximately 12,756 km, while the polar diameter is approximately 12,714 km.

• About 70.78% of the earth’s surface is covered with water.
  
• Ninety-seven percent of the water on the earth is salt water. 
• Salt water is filled with salt and other minerals, and humans cannot drink this water. 
• Although the salt can be removed, it is a difficult and expensive process.
  
• Two percent of the water on earth is glacier ice at the North and South Poles. 
• This ice is fresh water and could be melted; however, it is too far away from where people live to be usable.
  
• Less than 1% of all the water on earth is fresh water that we can actually use. 
• We use this small amount of water for drinking, transportation, heating and cooling, industry, and many other purposes.

• Ionosphere,tropsphere and stratosphere are separate layers of the atmosphere, while the point of contact or a transition zone between troposphere and stratosphere is called the tropopause. Hence option C is correct.

"Litho" is from the Greek word lithos, meaning stone. "Sphere" is from the Greek word sphaira, meaning globe or ball. The solid outer crust of any celestial body can also be called the lithosphere.

The term 'litho' is derived from the Greek word 'lithos', which means stone or rock.

Verkhoyansk, located in Siberia, Russia, is widely recognized as one of the coldest permanently inhabited places in the world, experiencing extreme temperature ranges.

The continents are separated by large stretches of water called oceans. Oceans are a major part of the hydrosphere. They are all interconnected. The ocean waters are always moving. The three chief movements of ocean waters are the waves, the tides, and the ocean currents. The five major oceans are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean, and the Arctic Ocean.

The polar diameter (north-south) of the Earth is approximately 12,714 km.

The equatorial diameter (east-west) of the Earth is approximately 12,756 km.

Earth bulges at the equator, which is the middle region between the poles. This bulge occurs because of Earth's rotation. The poles are flattened, not bulged. The question has grammatical errors but the answer is clear.

The polar radius of the Earth is approximately 6,357 km.

The mean radius of the Earth is approximately 6,371 km.

The equatorial radius of the Earth is approximately 6,378 km.

For organisms to live, certain environmental conditions (such as proper temperature and moisture) must exist, and the organisms must be supplied with energy and nutrients (food). All the animal and mineral nutrients necessary for life are contained within Earth's biosphere.

Eratosthenes, a Greek mathematician and astronomer, is famous for calculating the circumference and radius of the Earth with remarkable accuracy using the shadows of the sun.

In the troposphere, temperatures decrease by an average of 6.5 degrees Celsius per one thousand meters, which works out to about 3.5 degrees Fahrenheit per thousand feet.

SI Units: Temperature is Degree celsius

One degree Celsius is an interval of 1 K, and zero degrees Celsius is 273.15 K. An interval of one Celsius degree corresponds to an interval of 1.8 Fahrenheit degrees on the Fahrenheit temperature scale.