Why does the amount of energy decrease if energy can not be created or destroyed?

Iron reacts with oxygen to produce iron oxide (rust). this reaction is represented in an equation as 4fe + xo2 → 2fe2o3. identify the value of x that will balance the equation.

Are the earth's ocean floor and continents the same age geologically? why or why not?

Which phase of the cell cycle ensures that identical copies of the dna are made for daughter cells?