Two animals that can be found at the grand canyon include the abert’s and kaibab squirrels. the abert’s squirrel is found at the south rim of the canyon and in a few surrounding states. the kaibab squirrel, however, can only be found at the canyon’s north rim, mainly on the kaibab plateau. the kaibab squirrel is not found anywhere else in the world. scientists believe that the squirrels are actually closely related and have developed separately as a result of geographic isolation. it is possible that the squirrels were separated by plateau erosion that separated the forests and isolated the kaibab population. some scientists are studying if the squirrels are now two separate species or if the kaibab squirrel is simply a subspecies of the abert’s squirrel. separate species are unable to reproduce with each other. which evidence would be used to support the claim that the squirrels are two separate species?

The tasmanian devil, a marsupial carnivore, is facing extinction due to devil facial tumor disease (dftd) which causes bulging cancerous lumps and lesions to erupt around the face and neck — often causing enough deformation to make seeing or eating difficult. dftd has evolved into a contagious cancer, a trait that is unique among cancers. devil mating behavior involves biting around the head and neck, allowing cells from one individual — especially cells from the crumbly dftd tumors — to be transferred to the wounds or face of a new individual. this marsupial was once found across australia, but sea levels rose, isolating the tasmanian population, while the australian population went extinct. what would be an outcome of genetic isolation that is likely to have impacted the spread of dftd? a) reduced territory puts diseased individuals in greater contact with non-diseased ones. b) inbreeding results in less variation in facial features so the cancer is generally fatal. c) genetic isolation has made it difficult for scientists to develop a vaccine against dftd. d) the lack of genetic variation in the immune system of tasmanian devils minimizes resistance to the disease.

What would be the result if crossing over did not happen during meiosis in humans? a. there would be less genetic variation in humans. b. parents would be more likely to look like their children. c. the human population could not reproduce. d. children would have more chromosomes.

The image below shows a common blood pressure gauge. what does this device do? a. measures the level of oxygen present in the blood b. measures the pressure of blood when the lungs expand and compress c. measures the electrical activity of the heart d. measures the pressure of blood when the heart contracts and relaxes