This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Physiology
Surfactant synthesis stas after about 
Select and explain. 
A. 26 weeks of foetal life, B. 20 weeks of foetal life, C. 30 weeks of foetal life, D. 18 weeks of foetal life
B: 20 weeks of foetal life
Answer: B: 20 weeks of foetal life 
Explanation: Surfactant is synthesized and secreted by Type II alveolar epithelial cells, also called pneumocytes, which differentiate between 24 and 34 weeks of gestation in the human Ref: guyton and hall textbook of medical physiology 12 edition page number:312,313,314