What are two main features that characterize Homo sapiens?

The response highlights two fundamental features of Homo sapiens: bipedalism and cranial expansion. Bipedalism is a defining characteristic of hominins that allows them to walk on two legs, which not only influences physical adaptation but also has profound implications for social organization, tool use, and environmental interactions. The ability to walk upright has freed the hands for tool manipulation and has increased the range of vision to scout for food or potential threats.

Cranial expansion refers to the increase in brain size relative to body size in Homo sapiens, which is associated with advanced cognitive abilities. A larger brain supports more complex mental processes, including problem-solving, social interactions, and the capacity for abstract thinking. This expansion has been crucial for the development of language, culture, and social networks, which are hallmarks of the species.

While other choices present important aspects of human evolution or behavior, they do not capture these two primary features as fundamentally as bipedalism and cranial expansion do. The significance of these features goes beyond mere physical characteristics; they represent evolutionary adaptations that have enabled Homo sapiens to thrive in diverse environments and develop complex societies.