<span>Country is need in calculating your ecological footprint because it's a summed in were you are getting thing. Like from Wal-Mart or a famer market</span>
D - Copper and Gold. They both are used throughout in our moderen techonolgy; such as cell phones, computers, refrigerators, etc..
Good luck!
Answer:
Deuterium
Explanation:
Deuterium is an isotope of hydrogen with one proton and one neutron in its nucleus.
Thus it has a mass number 2.