Juniper is a desert plant that produces toxins. Unlike most animals, a type of rodent called Stephen's woodrat is able to eat juniper plants. The woodrat has special liver enzymes to metabolize juniper toxins. Which of the following statements best explains why the special liver enzymes became common in the woodrats? A. The enzymes allow the woodrats to grow much larger. B. The enzymes make the woodrats poisonous to their predators. C. The enzymes reduce the genetic diversity and variety of traits of the woodrats. D. The enzymes increase the ability of the woodrats to survive and pass on their genes.