Final answer:
Neonates receive antibodies from colostrum, the mother's first milk rich in immunoglobulins, and through the placenta via IgG for passive immunity within the first 24 hours postpartum.
Step-by-step explanation:
Neonates are provided with antibodies within the first 24 hours postpartum primarily through colostrum, which is the mother's first milk. This colostrum is secreted during the first 48-72 hours postpartum and is rich in immunoglobulins, particularly IgA, which confer gastrointestinal and systemic immunity as the newborn adjusts to life outside the womb. In addition to colostrum, the infant also receives IgG antibodies from the mother through the placenta, which is a form of naturally acquired passive immunity. This transfer of antibodies helps protect the newborn from pathogens while their own immune system is developing.