*emergency* in parkinson's disease, this insulating substance fails and prevents accurate neural transmission of signals. a. schwann cells b. nodes of ranvier c. cell body d. myelin sheath

19. a cell is viewed under a microscope and is found to have two nuclear envelopes and spindles that appear to be breaking apart. which phase of mitosis is the cell most likely in? a. metaphase b. prophase c. telophase d. anaphase