Although Darwin did not know about genes, he could see that animals of the same species who had slight variations that helped them to survive longer could produce more offspring than animals who were not as well equipped. Which of the following could be an example of a variation that would help a group of animals survive? A) black bears in a region that was always covered with snow

B) planting a certain kind of flower to attract butterflies

C) choosing a cat to take home from an animal shelter

D) turtles with long necks on an island where the food source was elevated