Which has been observed in the study of embryology? A. Species whose embryos have similar traits rarely have a common ancestor.
B. Species whose embryos have similar traits always have similar body forms as adults.
C. All traits present in early embryos remain throughout development.
D. Some traits in certain embryos disappear as the embryo develops.

D. Some traits in certain embryos disappear as the embryo develops

Explanation:

I don't know how I would explain it, but I can list some of the things that disappear such as...  Gill slits, and tails. Hope this helped :D

d is the answer

sorry if its wrong!

you did not attach the discourse, but i assume it to be the discourse on the origin and basis of inequality among men (the original titile in french is: "discours sur l'origine et les fondements de l'inégalité parmi les hommes"), also know as "second discourse". in this discourse, jean-jacques rousseau emphasizes that private property is the basis of all inequalities.

therefore, what enabled the old regime to maintain as long as it did was private property.