Final answer:
Children typically begin to roll from front to back by the end of the fourth month after birth and roll from back to front at a slightly later stage. By two months, infants can roll from their side to their back and engage with people they recognize.
Step-by-step explanation:
A child typically begins to roll from front to back by the end of the fourth month after birth. During this stage, they also develop the ability to lift their head 90 degrees while lying prone, sit up with support, and briefly hold their head steady. Infants roll from back to front slightly later as their muscles and coordination continue to develop.
By around two months, an infant can roll from their side to back and starts to exhibit social interactions like cooing and smiling at known individuals. It's important to note that each child may reach these developmental milestones at their own pace.
As infants grow into toddlers, their motor skills further advance. By their first birthday, most can pull themselves up to stand and start walking with or without help. Progress continues with more complex movements such as running, climbing stairs, and handling small objects as they approach the toddler stage.