Question

If you change a single base in a codon then

1.the codon could code for nucleic acids instead of amino acids
2.the codon could code for a different amino acid
3.the dna strand containing the codon could fall apart
4.the codon could automatically repair itself

Answer 1

The codon could code for a different amino acid.

The smallest alteration in the DNA base sequence will cause it to make a different amino acid.