An Rh-negative mother had an anti-Rh response following the birth of her Rh-positive child. The second fetus was also Rh+ so the maternal anti-Rh antibodies coated the fetus's erythrocytes with antibody. The isotype of these antibodies is

The isotype of these antibodies is igG

Explanation:

Anti-Rh response are employed by medical practitioners to define the Rh antigenic profile of human blood samples.

Fetal red blood cells are necessary for increasing the production of antibodies against Rh- antigens in Rh- women who are carrying a Rh+ fetus. The isotopes of the required antibodies is IgG.

The igG antibodies have high level of affinity and are present in blood, where they can make toxins, viruses, and bacteria ineffective, and activate the complement system.