I believe the answer is a definition.
Chemical equilibrium<span> is the state in which both reactants and products are present in concentrations which have no further tendency to change with time.
</span><span>Or, we can say that in chemical equilibrium the ratio between the concentration of the reactants and the products is constant.</span><span>
Chemical equilibrium is a result state when </span><span>the forward reaction proceeds at the same rate as the reverse reaction.
</span><span>Different reactions have different equilibrium.</span>
Answer:
Examples of Chemical Changes
Burning wood.
Souring milk.
Mixing acid and base.
Digesting food.
Cooking an egg.
Heating sugar to form caramel.
Baking a cake.
Rusting of iron.
Isotopes are two atoms with the same number of protons, but a different number of neutrons. Because they have the same number of proton they are atoms of the same element, but with different masses.
so, the answer is c.
i hope this will help you