During Life in Utero,oxygenation of the Fetus Occurs Through Transplacental

Multiple Choice

During life in utero,oxygenation of the fetus occurs through transplacental gas exchange.When birth occurs,four factors combine to stimulate the respiratory center in the medulla.The initiation of respiration then follows.What are these four essential factors?
(Select all that apply) .

A) Chemical
B) Mechanical
C) Thermal
D) Psychologic
E) Sensory