Remember that tonicity describes a solution based on whether cells stay the same size, shrink, or swell when placed in that solution. Red blood cell membranes are permeable to water. Thus if red blood cells are placed into solutions that are not isotonic, then water will cross the membrane. For each of the solutions below, determine if the solution is isotonic, hypotonic or hypertonic. To do this exercise, you need to know that Na and Cl- cannot permeate the red blood cell membrane, urea freely permeates the phospholipid bilayer of the red blood cell membrane, and glucose is actively transported across the red blood cell membrane. Red blood cell intracellular fluid is at 300 mOsm.

Over the past 60 years, many amphibian species have experienced significant population declines and some species have become extinct. scientists suspected that local human activities such as the destruction of wetlands, regional pollution, and deforestation were the main reasons for these losses. however, research over the past 20 years reveals significant amphibian population declines in protected areas of the world, such as nature preserves and parks. these global declines suggest widespread problems including increased ultraviolet radiation, acid rain, and disease. in switzerland, for example, 14 of the 20 native amphibian species are threatened with extinction. chytridiomycosis is a fungal disease first identified in 1998 as a cause of massive amphibian deaths. in some severely impacted populations, a few individuals have survived, perhaps because of some natural resistance. if these resistant individuals continue to survive and prosper, new resistant populations might emerge. this would be an example of the founder effect artificial selection genetic drift natural selection sexual selection

According to the cell theory, which describes cells? a. all organisms are composed of multiple cells. b. all cells have the same structure and function. c. cells are found in everything on earth. d. living organisms are not created spontaneously

5points what is term for the process of gathering information through images taken at a distance? o a. global positioning o b. topography o c. remote sensing o d. cartography submit