When a person is experiencing heartburn, he or she feels a burning sensation in the throat and midchest. think about thestructures of the digestive system. what most likely causes the burning sensation? the muscle at the end of the esophagus is not able to close, which allows stomach acid and digested food to go back upo into the esophagus. the villi in the small intestine are producing extra acid that is then concentrated at the pharynx. o the esophagus goes into muscle spasms while the salivary glands produce excess acido too much water absorption in the large intestine disrupts the ph of the digestive system, causing acid to reenter thestomach.

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.

How do temperature and salinity affect deepwater currents? they create changes in wind direction, moving denser water in the same direction as the wind and causing the deepwater circulation patterns found in the ocean. as temperatures and salinity levels of water increase, the water rises to the surface where it creates currents as it moves to colder regions. they create density differences that cause dense deepwater currents to flow toward the equator where they displace less dense, warmer water above them. they equalize the forces on undersea currents caused by the coriolis effect as they replace more dense water with less dense water.

Which enzyme is responsible for “unzipping" the dna by breaking the hydrogen bonds between the nucleotides?