Final answer:
The single greatest factor for low-birth-weight babies that could be prevented is lack of prenatal care.
Step-by-step explanation:
The single greatest factor for low-birth-weight babies that could be prevented is lack of prenatal care. Prenatal care refers to medical care during pregnancy that monitors the health of both the mother and the fetus. Lack of prenatal care can lead to various complications during pregnancy, including undernutrition, which is a major cause of low birth weight. Babies with low birth weight are more susceptible to disease and more likely to die in infancy.