Again, I think you are clueless. I agree there is much more nuance to the whole process with hormone gradients and things, but the embryo is its own thing, basically wrapped in a construction site and supplied with building blocks, no matter how hard you wish for the opposite.
And yes, that is pretty much comparable to digestion in a humans that are out of the uterus in the sense that they get stuff to break down, derive building blocks and build up again. The mother takes over the digestion part for embryos, but there is not more magic to this than that.