Which macromolecule catalyzes chemical reactions, thus be considered an enzyme?

proteins

Explanation:

Macromolecules are molecules that have a large size and are formed through the polymerization of smaller units. Some examples of macromolecules are nucleic acids, carbohydrates, proteins and lipids.

Enzymes are molecules that act by catalyzing chemical reactions, this means that these molecules accelerate the rate at which the reaction occurs (but does not affect the balance).

Enzymes are considered to be generally of a protein nature although there are some exceptions (such as ribozymes, which are composed of RNA).

Enzymes act on a substrate that will become a different molecule and be called a product.

it cools slower in the earth meaning the crystals have more time to form than lava on the surface