Answer:
1. antibodies from the mother cross the placenta and affect the fetus.
Explanation:
The hemolysis disease of the newborn occurs when a mother with Rh-negative conceives a baby whit an Rh-positive father triggering an immunological reaction in the baby if he/she inherits the Rh-positive factor from the father, the problem can develop if the baby´s red blood cells cross to the Rh-negative mother, the mother´s immune system sees the baby´s Rh-positive red blood cells as foreign and start to fight and destroy, as the moither´s antibodies destroy the red blood cells the baby becomes sick.
