Answer
The blank is filled with RNA
Explanation
As we know that there are three types of RNA responsible for protein synthesis.
1. mRNA
It is that type of RNA which is the exact copy of DNA template and contain the code copied from DNA for required protein.
2. rRNA
This RNA play a key role in the formation of ribosomes, a smaller organelle inside cell responsible for holding mRNA during protein synthesis.
3. tRNA
This RNA transport amino acids to the strand of mRNA and help in translation.