Question

What caused virtually all of Canada and some of the northern US to be once covered by thick glacial ice almost 15,000 years ago?
A. Changes in the earth’s climate caused the ice sheets to grow.
B. Changes in the orbit of the earth caused the ice sheets to spread across Canada.
C. The ice sheets were widespread because they were prevalent all around the world.
D. There is no apparent reason why the glacial ice was present.

Answer 1

What do you think is the most likely or unlikely?

Answer 2

The unlikely to me is C and D.

Answer 3

I agree with you. Now, from what I've studied, ice ages are caused by both climate changes and orbital changes are far we can tell. I'm not sure about 15000 years ago specifically. Does your book give any help? I'll look to see what I can find as well.

Answer 4

okay well my book kind of gives the answer,but idk. it says that the earth made small changes in the various wobbles of the earth's motion are sufficient to fundamentally shift the earth.

Answer 5

well, there's proof going both ways. No one actually knows as of yet. Since your book says orbit changes wouldn't do it, I'd say go with A.

Answer 6

Yea i was thinking tht too so yea i'll go with A.

Answer 7

If her book lists the wobbles as sufficient, than it is basing its answer on orbit change and not environmental climate. This becomes a word usage issue in both the question and source material, and not a true science question. If it was only a true science based question, than Laura would be correct in her statement that both are theories and neither has been proven or disproved.