Final answer:
A child typically begins to walk without assistance at around 13 months of age. Children may reach this milestone a bit earlier or later, which is considered normal up to 15 or 18 months. Cultural factors can influence the typical age range for walking, but the capability eventually develops in all children.
Step-by-step explanation:
In normal childhood development, a child is normally able to walk without assistance at around 12 to 15 months of age. Therefore, the closest answer would be B - 13 months. However, it is important to recognize that developmental milestones can vary from child to child.
For instance, taking the example of Louisa and Kimberly's children, Kimberly's son began walking at 10 months, which is earlier than the average, while Louisa's daughter, who is 14 months old, has not yet started walking. Louisa may be concerned, but it is also normal for some children to start walking up to 15 or 18 months. As children reach the age of two, they can perform more complex movements such as walking sideways, backward, and running, though they might fall often.
It is also important to consider cultural differences in childhood development, as shown by the Aché children who generally start walking much later due to their specific environmental context but later surpass peers in motor skills. By the end of the first year, most infants can stand with support, and by the time they are toddlers, they are refining their walking skills. Louisa's daughter might just be taking a little more time to reach this developmental milestone, which is within the normal range.