This is the normal nucleotide sequence on a dna strand: a—c—t—g—g—a—t what is a substitution?
a—c—t—g—c—g—a—t
a—c—t—g—a—t
a—g—t—g—g—a—t
a—c—u—g—g—a—u

Ans.

A substitution mutation can be defined as a mutation, which occurs due to exchange of a nitrogenous base for another (such as adenine to cytosine). This mutation can change the sequence of DNA and may results in a completely different gene product, sue to change in codon sequence.

The sequence 'A—G—T—G—G—A—T' represents a substitution mutation for normal nucleotide sequence as second base (cytosine) is exchanged with guanine in mutated sequence.  

Thus, the correct answer is option). 'A—G—T—G—G—A—T.'

Answer C,   A—G—T—G—G—A—T

Explanation:

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the dna molecules have a negative charge because of the phosphate groups in their sugar-phosphate backbone, so they start moving through the matrix of the gel towards the positive pole. power is turned on and dna fragments migrate through gel (towards the positive electrode).

explanation: