The flow of genetic information is DNA → mRNA → protein, as seen in figure 3 (to the right). In this way, DNA specifies what traits will be expressed in an organism. It is the number of nucleotides, as well as the specific nucleotide sequence of all the genes within an organism's DNA, that determines which proteins are created. Recall genes are coding sections of DNA that include the sequence necessary to build a protein. A protein is a biomolecule made up of amino acids that folds into a complex structure and has a specific function in an organism. A gene segment of DNA is shown in figure 4 (to the left).

According to the first paragraph, what determines the protein that is created?