Surfactant appears in amniotic uid at the gestational age of: (A) 20 wks, (B) 28 wks, (C) 36 wks, (D) 40 wks
Answer is B. Read below what Nelson has to say about the appearance of surfactant.
"Surfactant is present in high concentrations in fetal lung homogenates by 20 wk gestation* but does not reach the surface of the lung until later. It appears in the amniotic uid between 28-32 wks. Mature level of pulmonary surfactant is usually present after 35 wks".
Now I am leaving it to you to decide between 28 and 32 wks. I personally feel the answer should be 28 wks