it flows throght 11 countries and the 2nd question would be false. hope this helps
<span>In the west region of the US has natural sources like water, coal, oil, iron ore and lumber and there are a lot of forests and mining sites.</span>
Basically the study of rocks
<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.
