A vestigial structure is a structure that was helpful to an ancestor, but not helpful anymore.
A. Monkeys still have tails :/
B. Fishes still have fins :/
C. Some plants still have flowers :/
D. Humans don't have tails the last time I checked.
its like this, "if i give a plant an unlimited amount of sunlight,then the plant will grow to its largest possible size."
hope it let me know if it does or doesn't =^-^=