Final answer:
Humans tend to be weaned at a later stage of growth, especially in developed countries due to better nutrition and healthcare. Traditional societies may wean children earlier due to different nutritional practices and economic factors.
Step-by-step explanation:
Human Weaning and Growth
Humans are weaned at a later stage of growth compared to many other species. This is evident when considering the period of infancy, which is marked by the most rapid growth after birth, surpassing even the adolescent growth spurt. Advanced nutrition and healthcare in developed countries have contributed to a decrease in infant and child mortality rates, resulting in fewer instances where early weaning might be necessary due to survival pressures or the economic value of children.
In contrast, traditional hunter-gatherer societies and the developing world may practice earlier weaning due to differing nutritional sources and cultural practices. The grain-based diet that emerged with agriculture has introduced nutritional issues, such as lactose intolerance, to which humans continue to adapt.
Adulthood, characterized by three stages—early, middle, and late—brings further physical development with its own rewards and challenges. The timeline of a human's physical development illustrates that while growth in height happens early on, weight can continue to increase into adulthood, reflecting continued changes in body composition.