~Hello there!
Your question: Which rocky mountain state is directly north of Colorado?
Your answer: New Mexico is the rocky mountain state which is directly to the north of Colorado.
Hope this helps!
At first you have to write the variables out which are

now you have to combine like terms


now you add these two variables and end up with answer of
The correct answer is - the change of the total volume of water in the Earth's system.
The total volume of the water in the Earth's system is pretty much the same, and for it to change, and change the levels of the water in the oceans and seas, the Earth will have to go over a totally new conditions where either a new influx of water will reach our planet, or the heat will increase and the water will evaporate, for now that is not a possibility.