[Solved] Which of the following is a unique characteristic of viruses that distinguishes them from the other major groups of microorganisms? A) Lack cell structure B) Cannot be seen without a microscope C) Cause human disease D) Lack a nucleus E) Contain genetic material Micrographs: Photographic or digital images taken through a microscope to magnify objects that are too small to be seen by the naked eye. Cell Theory: Theory that all organisms consist of one or more cells, which are the basic unit of life; all cells arise by division of preexisting cells; and all cells pass hereditary material to offspring. Multicellular Organism: An organism composed of multiple cells that are specialized to perform distinct functions, contributing to the overall functionality and survival of the organism. Glucagon: Pancreatic hormone that encourages glycogen breakdown; increases blood glucose level.