The type of RNA that carries instructions from DNA in the nucleus to the ribosome in the cytoplasm is called messenger RNA (mRNA).
mRNA is synthesized during the process of transcription, where the DNA sequence of a gene is copied into a complementary RNA sequence. Once formed, mRNA exits the nucleus and enters the cytoplasm, where it serves as a template for protein synthesis during translation.
The ribosomes read the sequence of the mRNA in sets of three nucleotide bases, known as codons, each of which corresponds to a specific amino acid. This process ultimately leads to the assembly of proteins, which perform crucial functions in the cell.