Chemical reactions can create more complex products. What evidence best explains this phenomenon? Larger macromolecules breakdown into smaller macromolecules and combine during the reaction. The basic need for oxygen makes the element essential to create macromolecules. Water molecules combine to form complex macromolecules that the body needs. The molecular structure of complex macromolecules show that a chemical reaction has occurred.

The molecular structure of complex macromolecules show that a chemical reaction has occurred.

Explanation:

A macromolecule is defined as molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer.

Macromolecules are formed by chemical reactions between simple molecules which join together to give the macromolecule.

If we look at the structure of a macromolecule very closely, we will discover evidences that show that the complex structure of the macromolecule was created by stepwise chemical reactions.