: This is one of the most comprehensive sources. It offers answers for both the Living Organism Workbook and the Sphere of Life series .

: Biology relies heavily on terminology; use the search results to double-check spelling for terms like "eukaryote" or "photosynthesis."

: From algae and mosses to flowering plants. Kingdom Animals : Invertebrates ( worms , mollusks ) and vertebrates ( amphibians , and mammals).