A change in the sequence of bases along a DNA molecule✓Correct answer
Any change in an organism's appearance during its life
A change in which genes an organism chooses to use
A change in the environment that an organism lives in
Explanation
A mutation is a change written into the DNA itself, altering the order of the bases in which a gene's instruction is spelled out. A change in how an organism looks during its life leaves the order of those bases as it was, so it does not count as a mutation however striking it appears.