4. Which change to a DNA molecule would have the least effect on an organism? A: an addition to a base sequence at the beginning of a gene
B: a substitution in a base sequence that does not code for a protein
C: a substitution that creates a "stop" code in the middle of a gene
D: a deletion from a base sequence in the middle of a gene

Change in a single nitrogen base in the DNA sequence will not have any significant effect on the organism.

So A

Explanation:

This is known as point mutation and it does not have any significant change in the protein and it is least harmful type of DNA mutation.

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.

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