7. Which of the following about mutations is not true
a. A mutation is a change in a DNA sequence
b. All mutations are harmfull
C. All mutations occur randomly
d. Mutations can lead to evolution

B.)

Explanation:

Not all mutations are harmful because come animals mutate to help them adapt to their environment.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).