* Ribosomal RNA (rRNA): This is a type of RNA that provides the structural framework for the ribosome.

* Ribosomal proteins: These proteins bind to the rRNA and help to shape the ribosome, as well as facilitate the various steps of protein synthesis.

Together, rRNA and ribosomal proteins form two subunits:

* Small subunit: This subunit is responsible for binding to mRNA and initiating translation.

* Large subunit: This subunit contains the active site where peptide bonds are formed during protein synthesis.

So, in short, ribosomes are made of rRNA and ribosomal proteins, which combine to form two subunits that work together to synthesize proteins.