What happens to the total mass of a carbon and oxygen after they form carbon dioxide

What does the process of natural selection involve

In pqr m< p=60 m< q= 30 and m

Consider the following reactions. (note: (s) = solid, (l) = liquid, and (g) = gas.) mg(s) + ½o2(g) → mgo(s) + 146 kcal/mole h2(g) + ½o2(g) → h2o(g), δh = -57.82 kcal/mole what type of reaction is represented by the previous two examples?