Final answer:
The characteristics of an infant's stools change from meconium to seedy yellow stools or slightly formed tan stools when they are breast milk fed. Breast milk composition also changes during a single feeding, with foremilk and hindmilk serving different purposes for hydration and nourishment.
Step-by-step explanation:
The characteristics of the stools of an infant who is breast milk fed change over time and within a single feeding. In the first few days after birth, the infant passes meconium, which is a tarry, greenish black stool that is sterile and devoid of bacteria. As the infant starts consuming breast milk, the stools transition to seedy yellow stools or slightly formed tan stools. Breast milk composition also changes during a single feeding, with foremilk being watery and translucent to quench the infant's thirst, and hindmilk being opaque, creamy, and rich in fat to satisfy the infant's appetite.