What type of immunity is described as occurring when antibodies pass from a mother to her child during pregnancy?

The correct answer is Passive Natural Immunity because this form of immunity occurs when antibodies are transferred from one individual to another without the individual's immune system actively producing those antibodies. In this case, during pregnancy, a mother naturally transfers antibodies to her fetus through the placenta. This transfer provides the newborn with immediate protection against certain infections until its own immune system becomes fully functional.

This method is considered "natural" because it occurs through biological processes without any medical intervention, as opposed to artificial methods where antibodies might be administered through injections or treatments. Passive immunity is characterized by the short-term protection it provides, as the antibodies received from the mother do not last indefinitely and are gradually broken down by the child’s body. This defense mechanism is crucial for newborns in the early stages of life when their immune system is still maturing.