Question 12 of 20 Select the best answer for the question
12. When did oxygen levels start to decline from 35 percent down to today's levels?
O A. During the Permian eriod
> O B. Before the Siluran period
C. After the Triassic period
Oo. Ater the Caroonferous period
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After the Carboniferous period

Explanation:

The oxygen levels start to decline from 35 percent down to today's levels "After the Carboniferous period." This is the period of about 298 million years ago after 60 million years of Carboniferous period which began around 358 million years ago. It was characterized by dense and swampy forests, which led to large deposits of peat.

there is no image for me to refer

explanation: we can only guess at how our actions may be perceived in the future. doing something really big like killing lots of people, saving lots of people, affecting the lives of lots of people is a sure fire way of being remembered in historical records. we can also make a difference in the history records by being a small influence on something bigger, whether that is as a civil servant, scientist or artist.

of course you could argue that we all affect history just as tiny cogs in a   bigger machine.

if you mean how do people influence our opinions of things which have already happened, then simply by writing a book which looks at things form a different perspective and trying to convince people that this perspective is more accurate or truthful. people do it all the time i.e. richard the third was a terrible or was he? plenty would disagree, it's just that their views aren't the most widely known.n: