A Newborn Is Placed Under a Radiant Heat Warmer

A newborn is placed under a radiant heat warmer.The nurse knows that thermoregulation presents a problem for newborns because:

A) Their renal function is not fully developed,and heat is lost in the urine
B) Their small body surface area favors more rapid heat loss than does an adult's body surface area
C) They have a relatively thin layer of subcutaneous fat that provides poor insulation
D) Their normal flexed posture favors heat loss through perspiration