* Proteins are the workhorses of the cell. They have a vast range of functions, including:

* Enzymes: Catalyze (speed up) chemical reactions.

* Structural components: Provide shape and support to cells and tissues.

* Transport: Carry molecules across membranes.

* Signaling: Relay messages within and between cells.

* Defense: Antibodies protect against pathogens.

* DNA stores genetic information, but it doesn't directly interact with the external world.

* RNA plays a role in protein synthesis, but its primary function is to act as a messenger between DNA and ribosomes.

* Ribosomes are the cellular machinery that builds proteins, but they don't directly interact with the external environment.

Therefore, proteins are the type of molecule that allows us to interact with the world around us.