Here's how it works:

* Food: The mother's blood carries nutrients from the food she eats to the placenta. The placenta then transfers these nutrients to the developing embryo.

* Oxygen: The mother's blood also carries oxygen to the placenta. The placenta passes this oxygen to the embryo.

* Waste Removal: The placenta also removes waste products from the developing embryo and passes them back to the mother's bloodstream to be excreted.

This exchange of nutrients, oxygen, and waste products is vital for the healthy growth and development of the embryo.