12.So, as odd as the starfish body plan seems, something about it was successful -- from their ancient bilateral ancestors, to the radial crinoids with their upward-facing arms, to the predatory, downward-facing starfish.
因此, 尽管海星的
体计划看起来很奇怪,但它的某些方面
成功的——从它们古老的双侧祖先,到手臂朝上的放射状海百合,再到捕食性的、面朝下的海星。机翻