Which part of the chemical equation is incorrect?

Thus the coefficient of oxygen is incorrect.

Explanation:

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 given chemical equation for combustion of butane is

The balanced chemical equation for combustion of butane is :

Thus the coefficient of oxygen is incorrect.

"a.) well–developed vascular system."

and after water is usually warmed by the sun the water temperature raises and then evaporates .