Question

Answer the following in 75-100 words.

1) 'Life would not have existed on Earth without the presence of the atmosphere.' Support this
statement with suitable reasons.
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Answer 1

The atmosphere is important for many reasons. Before we talk about why it is important we should define what the atmosphere is. The atmosphere is the layer of air that surrounds a planet. Earth has an atmosphere that is just right for humans, animals, and plants to live in. The gases in the atmosphere act like a blanket keeping our planet warm plus the atmosphere contains oxygen something we (humans and animals) all need to breathe.

Many planets in our solar system have a atmosphere. Venus for example has such a thick atmosphere most of the sun's energy gets trapped making the surface of Venus 864 degrees Fahrenheit! That is hotter than an oven! Mars also has an atmosphere but it is too thin making the surface of Mars -80 degrees Fahrenheit! Plus the atmospheres of Venus and Mars do not contain the oxygen we all need to breathe.

Our atmosphere allows just enough of the sun's energy back into space so that we do not get to hot like Venus or too cold like Mars. If Earth had no atmosphere, apart from having no air to breathe, the surface of the Earth would be 0 degrees Fahrenheit.

These are just two of the reasons why are atmosphere is important. The atmosphere contains the warmth we all need to survive, the oxygen we all breathe, and carries the rain we all need. Without our atmosphere life as we know it would cease to exist.

Answer 2

Answer:

• In the atmosphere Oxygen (21%) is one of the major component.

• Oxygen is essential for the survival of all living organisms.
• Other essential gases like nitrogen (78%),argon (0.9%), carbon dioxide (0.04%) ,that support life on the earth, are present in the atmosphere.
• Most organisms use oxygen for respiration;
• Nitrogen  produces (by lightning and bacteria) ammonia that is used to make nucleotides and amino acids;

• Plants use carbon dioxide for photosynthesis and release Oxygen.  
• Water cycle would not have been possible without the atmosphere.

Hence , we can say 'Life would not have existed on Earth without the presence of the atmosphere'.