Why should a scientist repeat the same experiment several times before reporting the results? Helpp

Accuracy in the translation of mrna into the sequence of amino acids in a polypeptide depends on specificity in which of the following? 1) binding of ribosomes to mrna 2) shape of the a and p sites of ribosomes 3) attachment of amino acids to trnas 4) bonding of the anticodon the codon and the attachment of amino acids to trnas