I think is alternative a because that includes the earth
<u>Answer:
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The build-up of three oxygen created our ozone layer around two billion years ago.
<u>Explanation:
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- The ozone layer is a part of the stratosphere which is located right after the troposphere in the atmosphere of the Earth.
- The ozone gas is made up of the abundance of three oxygen molecules combining with the ultraviolet radiation emitted by the Sun.
- The development of the ozone layer happened around two billion years ago when the oxygen concentration levels on the planet began to rise slowly and gradually.
It is a false statement that the <span>Appalachians, the oldest North American mountains, are an example of upwarped mountains. The correct option among all the options that are given in the question is the second option. The Appalachians are examples of folded mountains. I hope the answer has helped you.</span>
Answer: I dont understand you question
Explanation:
