You are comparing two samples of the octopus genome, one from an octopus that can make ink (sample 1), and one from an Octopus that can't make ink (sample 2). You notice the one who can't make ink has a mutation Sample 1: ATTACAGTACTGGCA Sample 2: ATTACAATACTGGCA
Looking at the sequences carefully you determine it is a
mutation
A. Insertion
B. Substitution
C. Deletion
D. Inversion

Substitution Mutation

Explanation:

It can’t be deletion or addition as the base pairs of DNA haven’t shifted to the right or left.

If they had the second sequence would have an extra/one less base pair which isn’t the case.

It can’t be an inversion, as that’s where the base pairs from the opposite DNA strands are inverted/switched.

If it was inversion, you would have had a C instead of an A for Sample 2.

This is due to complementary base pairing where guanine bind with cytosine and adenine binds with thymine.

Therefore, this only leaves substitution as a viable answer.