I would assume its c but i cannot be 100% but im 100% sure its A or C because cool air falls warm air rises
When tectonic plates are pushed together this creates folded mountains. It's created through the process orogeny.
We can not say that this areas are not civilized or to call them backwards. We may call them different. We can take for example the uses of animals in order to expand the commerce of their area. If we research about the use of camels, for example, we could see that it gained an special place within those who wanted to travel through many difficult areas like deserts. So in the case of camels they were not backwards, they used a different method to obtain success
Answer:
Option (A)
Explanation:
In the above-given question,
Option (B) is wrong with it's usage of the modifier "how'' in the sentence. If the modifier is used in one place (how heat from the inner core flows), it should also be used in the continuing clause (how the formation and periodic reversal).
Options (C) and (D) are wrong in using the word "are" for the whole sentence as there is no need to use this word. The verb form will depend on the subject, in this case, is "the discovery that earth's inner core" which is singular in nature. Thus, the verb form will be -is and not -are.
Option (E) is wrong for it's use of the comma. If the comma is used, then the whole sentence is not a full-fledged sentence but rather a dependent clause with no resolution.
The correct answer for the given passage is option (A).