参考答案

正确答案：D
解析：本题的四个选项中，只有D项为正确答案。这可从文中的“There they remained and in time grew into baby oysters called seed or spat(贝卵)．The spat grew larger by drawing in seawater from which they derived microscopic particles of food．Before long，farmers gathered the baby oysters，transplanted them in other waters to speed up their growth，and then transplanted them once more into anotherbody of water to fatten them up．”推知，即它们会呆在那儿并逐渐长成小牡蛎。我们称之为种子或贝苗。贝苗吸进海水中的微小生物作为食物从而越长越大。不久之后，农夫将这些小牡蛎收集起来，把它们移种进其他的水域加快其生长，然后再次将它们移种进另外的水域以使其肥壮起来。