Each individual blastomere of an early-stage embryo is considered to be totipotent. However, there is a “critical mass” requirement for an embryo to develop into a viable offspring. Explain why.

Explain how a synchronous and/or uneven cleavage leads to early differentiation into inner cell mass and trophoblast tissue.

If you non-surgically collected embryos from a donor cow on day 7 when you would expect morulae or blastocysts, but recovered a number of morphologically normal 12-cell embryos, they would be considered degenerate. Why?