This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
Fetal placenta derived from which layer: 
Select and explain. 
A. Zonabasalis, B. Zona capsularis, C. Zona parietalis, D. d. Inner cell mass
A: Zonabasalis
Answer: A: Zonabasalis 
Explanation: Ans-A Zona basalisRef: D.C. Dutta 8th ed. / 32SAILENT FEATURE OF PLACENTA* Wt-500gm* Wt of placenta: wt of fetus= 1: 6* Human placenta is discoidal(disc shape) and deciduate(shed off during delivery), hemochoroidal (in contact with maternal blood)* Formed at decidua basalis* Formed by trophoblast.* Placental circulation established at 21-22ndday(same time heart is formed, hence fetal circulation is established.)