James observes DNA sequences and notices a change in Sequence 2 from Sequence 1. Two DNA sequences are pictured. Sequence 1 shows letters in the following sequence, with T highlighted in the 2nd to last sequence of the first row, and A highlighted in the second to last sequence in the second row: Sequence 1, First row: CAC, GTG, GAC, TGA, GGA, CTC, CTC. Sequence 1, Second row: GTG, CAC, CTG, ACT, CCT, GAG, GAG. Sequence 2 shows letters in the following sequence, with A highlighted in the 2nd to last sequence of the first row, and T highlighted in the second to last sequence in the second row: Sequence 2, First row: CAC, GTG, GAC, TGA, GGA, CAC, CTC Sequence 2, Second row: GTG, CAC, CTG, ACT, CCT, GTG, GAG James’ work in a genetics lab helps him recognize what this change represents. Choose the words or phrases to finish the sentence. This sequence shows an example of a(n) Choose... because it has a(n) Choose... .