In terms of climate, which factor has the most impact and why?

What exactly do you mean 

It is the doctrine that the us had the right and duty to expand throughout north america. it just means they believed they had the right to expand westward and they did! they stated with the 13 colonies and then they kept moving gaining different territories throughout the years

Ithink it is space that makes up 70 percent

Answerscripps institution of oceanography; i believe this is correct plz check first good luck;