Engine tidak akan bisa berfungsi apabila hanya terdapat system pengapian dan system bahan bakar, Agar bisa berfungsi ditambahkan salah satu factor yaitu:​

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

Answerair masses develop near the equator are warm; tropical air mass