专题文章
时长:00:00更新时间:2023-11-17 14:01:02
Aneggshellistheoutercoveringofanegg.Itisthinandbrittle,andcanbewhiteorbrowndependingonthebreedoftheegg-layinganimal.Eggshellsarecomposedofcalciumcarbonate,whichisthesamematerialfoundinseashells,limestone,andchalk.Theyserveasaprotectivebarrierforthedevelopingembryoinsidetheeggandalsohelpregulatetheexchangeofgasesandmoisturewiththeoutsideenvironment.
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