earth science: exploring planet earth - part 21 of 35. earth science embraces broad areas of study. since ancient times, humans have tried to discover the secrets of earth. we have studied the motions of celestial bodies, made observations on volcanic act - 三葉蟲 個影片檔及 b 捲影像00:33
crustaceans (lobsters, barnacles, shrimp. and their relatives) - part 2 of 24. illustrates the structures, functions, and habitats of the most important types of crustaceans, including the fairy shrimp, plankton, barnacles, crabs, lobsters, and crayfish. - 三葉蟲 個影片檔及 b 捲影像00:35