The Example of Ocean and Lake Stickleback Fishes Indicates That

The example of ocean and lake stickleback fishes indicates that morphology can be altered

A) by altering the expression of a developmental gene in some parts of the body but not others.
B) by environmental factors (in this case,pollution) .
C) by the elimination of a gene (Pitx1) from a population,which leads to loss of the trait (body armor and spines) .
D) only by changing the sequences of protein- coding genes.