What is a key milestone for nine-month-old children?

At nine months old, a key milestone for children is their ability to sit independently and engage in babbling. At this age, most infants can sit without support, which enhances their ability to explore their environment and interact with caregivers. Babbling is also an important aspect of language development; it signifies the beginning of communication skills as infants start to experiment with sounds. These milestones reflect significant advancements in motor skills and cognitive development, indicating that the child is developing the ability to coordinate their movements and start forming the foundation for future language acquisition.

In contrast, some of the other options represent milestones that typically occur later in development. For instance, walking with support usually happens around 9-12 months, while running is a skill that generally develops after the first year. Pointing to body parts usually emerges after 12 months as children start to understand and follow simple instructions. Thus, sitting and babbling are indeed key milestones that accurately characterize the developmental stage of a nine-month-old child.