How does a decrease/decline in a top predator impact biodiversity in an ecosystem?

Which of the following scenarios is the best example of evolution? a a particular species of flowers in a meadow were pollinated by bees for several hundred years. over time, fewer and fewer bees can be found in the meadow. some hummingbirds are attracted to a few of the plant species with brightly colored flowers. over time, more of the plant varieties now have brightly colored flowers. b.a mouse is nearly caught in a mouse trap. the mouse learns through that experience to stay away from mouse traps and teaches her offspring to avoid mousetraps. mice are no longer caught in mousetraps. c. a tidal wave removes all of the grass on an island. d. a population of mice lives in a forest. a species of tree is introduced which reduces the amounts of nuts available for the mice. there does not appear to be a change in the mice over time.