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.

Explanation:

To find the time taken given the velocity and distance covered we use the formula

From the question we have

We have the final answer as

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