1. Which scientific concept did Charles Darwin and Alfred Wallace independently discover? a. Mutation c. Overbreeding b. Natural selection d. Sexual reproduction 2. Which is the best definition of adaptation? a. A trait or behavior that aids an organism's survival and reproduction b. A heritable trait or behavior that aids an organism's survival and reproduction c. A trait or behavior that aids a population's survival and reproduction d. A heritable trait or behavior that aids a population's survival and reproduction. 3. Which is an example of an adaptation? a. The better nutrition of a human helps her grow taller. b. The webbed feet of a duck help it swim. c. The urban location of a raccoon helps it find food. d. The large leaves of a desert plant require more water. 4. What are homologous structures? a. Physical structures that have no apparent function. b. Parallel structures in diverse organisms. c. Physical structures that are used only occasionally. d. Similar structures in diverse organisms.