Final answer:
Meconium is the black, sticky substance found in the diaper of a 1-day-old baby. It is the baby's first stool and is a normal occurrence. In some cases, babies may pass meconium in the womb, which can cause complications.
Step-by-step explanation:
The black, sticky substance in the diaper of a 1-day-old baby is called meconium. Meconium is the baby's first stool and is a normal occurrence. It consists of substances that have accumulated in the fetal intestines during pregnancy.
Meconium is usually passed by the baby after birth, but in some cases, 5-20% of babies may have a bowel movement in the womb, which can cause complications. The first sign of passing meconium is usually when the amniotic sac ruptures and the amniotic fluid is stained with a greenish or yellowish color.