“突出物”用英语怎么说？

大量芽状突出物形成,并被脱出以获得微细胞.A larger number of budlike protuberances form and are pinched off to give microcells.从这一观点来看,城市是个象山岳一样的自地面升起的突出物.From this standpoint the city is an elevation, rising from the ground like a mountain....