When does the blastocyst form

Answer: Blastocyst forms 5 days after fertilization

Explanation: Blastocysts usually forms in early development of an animal or human.

The blastocyst inner cell mass is the source of true embryonic stem cells capable of forming all cell types within the embryo. In humans, blastocyst stage of development occurs during the first and second week following fertilization (GA week 3 and 4) and is described initially as Carnegie stage 3.