49) a research team began a study of a cultured cell line. their preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence. what could they conclude right away?; a) the cells originated in the nervous system.; b) the cells are unable to form spindle microtubules.; c) they have altered series of cell cycle phases.; d) the cells show characteristics of tumors.; e) they were originally derived from an elderly organism.