Question

how did the discovery of the rhesus factor affect society?
more patients died from having a transfusion with the wrong rhesus factor.
new treatments during pregnancy could prevent harm to the developing child.
less donated blood could be used in the treatment of patients.
the number of blood types was reduced by half.

Explanation:

The rhesus (Rh) factor discovery helped in understanding blood compatibility. For pregnancy, if a mother is Rh - negative and the fetus is Rh - positive, it can cause issues. The discovery led to new treatments (like Rh immunoglobulin) during pregnancy to prevent harm to the developing child. The first option is wrong as the discovery should reduce such deaths. The third is wrong as it should help in better blood usage. The fourth is wrong as it doesn't reduce blood types. So the correct option is about new pregnancy treatments.

Answer:

B. New treatments during pregnancy could prevent harm to the developing child.