Which age grouping includes both newborns and infants?

The age grouping that includes both newborns and infants is from birth up to 1 year old. This period encompasses the entire developmental stage of a newborn (which is considered to be the first 28 days of life) and extends to the first year of life, during which the child transitions through various stages of infancy.

This choice effectively captures a broad range of early development, highlighting the significant growth and changes that occur in a child's first year, including physical, cognitive, and emotional development. The classification as "0-1 year old" ensures that both newborns and those slightly older, typically referred to as infants, fall within this age range, making it the most comprehensive option for understanding this developmental phase.

By identifying the correct age grouping, it becomes clear how these early stages are crucial for health and developmental practices that are essential for caregivers and healthcare providers working with very young children.