The "rungs" of an RNA ladder are actually made of nitrogenous bases. Here's a breakdown:

* RNA Structure: RNA is a single-stranded nucleic acid. It looks like a ladder that's been twisted into a helix.

* The Rungs: The "rungs" of this ladder are formed by pairs of nitrogenous bases that connect the two strands of the RNA molecule.

* Base Pairing: These bases pair up specifically:

* Adenine (A) always pairs with Uracil (U)

* Guanine (G) always pairs with Cytosine (C)

Key Points:

* The rungs of an RNA ladder aren't made of actual physical "rungs" like you'd find on a regular ladder. They are formed by the chemical bonds between the nitrogenous bases.

* The sequence of these bases in RNA holds the genetic information that tells the cell how to build proteins.

Let me know if you'd like to learn more about the structure or function of RNA!