भ्रूण (embryo) स्वयं को तीन अलग-अलग परतों में अंतर करना शुरू कर देता है जिन्हें किस रूप में जाना जाता है?

The protective fluid that surrounds and cushions the developing embryo inside the gestational sac is called:

A nurse educating postgraduate nursing students explains early embryonic development. Which finding best confirms that an embryo has progressed beyond the morula stage but has not yet implanted?