what are the missing words? each gene codes for a particular combination of __________ __________ which makes a specific protein

The missing words are "amino acids." So the complete sentence is: Each gene codes for a particular combination of amino acids which makes a specific protein. Genes code for proteins by specifying the sequence of amino acids in the protein, with each set of three nucleotides (a codon) in the gene corresponding to one amino acid in the protein chain. This sequence of amino acids determines the structure and function of the protein.