"D" IN SCIENCE
'(<a href="http://www.j-archive.com/media/2007-05-11_DJ_06.jpg" target="_blank">Sarah of the Clue Crew shows a micrograph of an organism with radial symmetry on the monitor.</a>)  A grungy type of earth used as industrial filler is named for these beautiful symmetrical algae from which it's made'
diatoms