Answer:
C. More people have moved to urban areas.
Explanation:
Answer:
The oil sands are a strategic resource that contributes to economic opportunity and energy security for Canada, North America and the global market. The oil sands comprise 167.2 billion barrels of crude oil – 97 percent of Canada’s 172.5 billion barrels of proven oil reserves – and are a vital part of the Canadian economy.
Source: nrcan.gc.ca
1 and 2 because its nature
<u>Answer:
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The build-up of three oxygen created our ozone layer around two billion years ago.
<u>Explanation:
</u>
- 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.
Answer:
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