men preparing tree seedlings - red pine - and loading them onto trucks / hands stuffing groups of plants into wooden box, pressing down with feet /... - 美國赤松 個影片檔及 b 捲影像01:51
gymnosperms - part 6 of 29. demonstrates that gymnosperms are seed plants which bear their seeds on cones. animation and time-lapse sequence trace the life cycle of the pine through the growth of the pollen and seed cones, pollination, fertilization, and - 美國赤松 個影片檔及 b 捲影像00:29
