Which antibody accounts for 8085% of serum antibodies, can cross the placenta, and is responsible for Rh reactions? 23:21 Biology Which antibody accounts for 8085% of serum antibodies, can cross the placenta, and is responsible for Rh reactions? a. IgA b. IgD c. IgE d. IgG e. IgM Answer: d Learn More : Share this Share on FacebookTweet on TwitterPlus on Google+