During gestation, embryos normally develop in

During gestation, embryos normally develop in humans which happen in the eleventh week. An embryo is then called a fetus in a more advanced stage of development. Unlike humans, animals which develop in eggs outside the mother's body would be then called as chick embryo.

The missing word in the sentence above is humans. 

Made up of dna, long, and bro thats pretty much th rnd of my answer becausr