Solved by a verified expert:1. Fleas are becoming resistant to the topical medications used for flea prevention in dogs. Which of the following best explains this observation?A. Prolonged contact with the flea medicine causes mutations in the fleas that are exposed, causing some of them to develop resistance.B. Some fleas are naturally resistant to the pesticide and are thus harder to kill. It is these fleas that survive to reproduce, and the flea population starts to increase.2.Which of the following is the best definition of evolution?A. A species changes its physical make-up over time in order to better fit its environment.B. The gene frequencies of a population change over time.C. When an individual changes in response to its environment, we say that evolution has occurred.3. In terms of evolution via natural selection, which of these statements is true?A. Individuals are selected, and populations evolve.B. Populations are selected, and individuals adapt.4. Different species of hummingbirds have beaks of different shapes; the beak of each is curved to precisely fit into the flowers from which they sip nectar. Which of the following statements is true regarding this kind of selection?A. Natural selection favors those birds whose beaks are best suited to fit into the flowers. Over time, if mutations or recombination produces individuals whose beaks are a better fit, and this improved their survival, they can eventually replace individuals with beaks that don’t fit into the flowers as well.B. Natural selection will favor those species whose traits will help them the best now and in the future; it intentionally eliminates the less well-adapted individuals in favor of those that will eventually lead to a population that contains individuals that are extremely well adapted to their environment.