Which of the following can reduce biodiversity within a natural environment? A. Yucca moths pollinate and feed on yucca plants in the Mojave Desert. B. Red-billed oxpeckers eat ticks off of impalas' coats in the grasslands of East Africa. C. Non-native American bullfrogs out-compete native amphibians in the Tropical Andes. D. Giant kangaroo rats enrich the soil for plants with their piles of grass clippings in the California grasslands.