The answers to this question is b, I did this on Plato
Answer: 
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here iron is having an oxidation state of +3 called as
cation and oxide
is an anion with oxidation state of -2. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral
.
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

The correct answer that would best complete the given statement above is option B. Heat in a substance is an example of a kinetic energy. Kinetic energy is a kind of energy that is in motion. We can feel the kinetic energy of heat through their temperatures because heat is being transferred.
Most of the surface of the earth is covered with water and looks blue from space.
Answer:
the change is evaporation
Explanation:
the water heats up at the surface of the water and evaporates