Which type of immunity is inherited at birth due to maternal blood and genetic factors?

The correct answer is natural immunity because it refers to the innate immunity that a newborn receives from their mother through the placenta during pregnancy and through breast milk after birth. This form of immunity provides the baby with essential antibodies, particularly immunoglobulin G (IgG), which helps protect against infections in the early months of life.

Natural immunity is critical as it gives the infant immediate defense mechanisms without requiring exposure to specific pathogens. This form of immunity is not the result of vaccinations or external interventions, which is why it's classified differently from active immunity, where the body produces its own antibodies as a result of infection or vaccination, and artificial immunity, which is gained through deliberate exposure to an antigen through vaccines. Cell-mediated immunity pertains to the immune response involving T-cells and does not directly relate to the antibodies passed from the mother to the child.

Understanding natural immunity's role helps clarify the biological advantages provided to newborns and the importance of maternal health during pregnancy.