Fluorescent FM dyes partition reversibly into biological membranes without penetrating through them. Suppose that you have neurons cultured in a dish, and you incubate them with an FM dye for a period of time before washing the cells with excess medium to remove the dye. a)You find that if you stimulate the neurons to trigger action potentials during incubation with the dye, the synaptic regions of the neurons remain fluorescent after the wash. Propose an explanation for this effect. b)After you have generated fluorescent synaptic regions by this procedure, suppose that you trigger further action potentials while continuing to wash with excess medium. Would you expect the synaptic regions to lose fluorescence

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

To maintain asepsis when administering an injection, all parts of the syringe can be handled except the:

Which of the following statements is accurate about evolution? question 10 options: natural selection only eliminates odd individuals. evolution means that a population never has changes in its genetic frequencies. mutations are always harmful. evolution means that a population undergoes changes in its gene frequencies over time.