The RNA that exits the nuclear pores to the cytosol on its way to the ribosome is called messenger RNA (mRNA).

Here's a breakdown:

* mRNA is a single-stranded RNA molecule that carries the genetic code from DNA in the nucleus to the ribosomes in the cytoplasm.

* Ribosomes are the cellular machinery responsible for protein synthesis.

* Nuclear pores are channels in the nuclear envelope that allow molecules to move between the nucleus and the cytoplasm.

So, the process goes like this:

1. DNA in the nucleus contains the genetic code for proteins.

2. Transcription occurs, where the DNA code is copied into mRNA.

3. mRNA exits the nucleus through nuclear pores.

4. mRNA travels to a ribosome in the cytoplasm.

5. Translation occurs, where the mRNA code is used to assemble amino acids into a protein.