What developmental milestone is typically achieved when a child can sit without support for long periods?

The achievement of sitting without support for long periods is a key developmental milestone that reflects a child's increasing strength, balance, and coordination. Typically, most children can sit independently around 6 to 8 months of age. By 9 months, children often demonstrate the ability to sit without support for extended periods, allowing them to engage in play and interact with their environment more effectively.

This milestone is significant because it lays the foundation for further physical development, such as crawling and eventually walking. Reliable sitting also enhances a child's cognitive and social interactions. At this stage, children begin to explore their surroundings more actively, which contributes to their overall development.

In contrast to the other ages provided, while some children may begin sitting unsupported around 7 or 8 months, consistently sitting for longer durations is more characteristic of the 9-month mark, making this the most accurate answer.