Tag: introduction to the spheres of the earth

Approximately 97.5% of Earth's water is saline (oceans), while only about 2.5% is freshwater, much of which is locked in glaciers and ice caps.

Artificial satellites orbit the Earth in the thermosphere and exosphere. Among the choices provided, the thermosphere is the correct region where many low Earth orbit satellites are located.

Earth is the only known planet where various forms of life like, plants, animals etc. are present. It makes earth unique from other planets. So, the correct option is A.

The faint band of stars seen across the night sky is the view of the Milky Way's galactic disc from our perspective inside the galaxy.

While estimates vary, current astronomical models often cite approximately 100 billion (1,00,000 million) galaxies in the observable universe.

Stars twinkle because their light is refracted by Earth's atmosphere. Planets, being closer, appear as discs rather than point sources, so their light is less affected by atmospheric turbulence, making them appear to glow steadily.

The solar system consists of eight recognized planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was reclassified as a dwarf planet in 2006.

Approximately 2000-2500 stars are visible to the naked eye under ideal dark sky conditions. This number represents stars with apparent magnitude brighter than about 6.

The biosphere is the global sum of all ecosystems, representing the zone of life on Earth. It includes all living organisms and their interactions with the lithosphere, hydrosphere, and atmosphere.

Man and biosphere programme is an international biological programme of UNESCO (United Nations Educational Scientific and Cultural Organization) which was started in 1971 but was introduced in India in 1986.