[ 361 ] Life Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • As seen in the following diagram, living things are highly organized, with specialized structures performing specific functions at every level of organization. specialized cell tissue organ system organism Select the correct sequence of cellular organization. Begin with the most specialized component. A. red blood cell → blood → heart → cardiovascular system B. cardiovascular system → heart → blood → red blood cell C. red blood cell → blood → cardiovascular system → heart D. heart → cardiovascular system → blood → red blood cell