In the context of early human development necessary for survival in cold environments, the most relevant factors would be:
-
Finding shelter in caves - This is crucial for protection against the elements and predatory animals, providing a safe place to rest and maintain body heat.
-
Banding together in clan groups - Social cooperation is vital for survival in harsh conditions, as groups can share resources, hunt together, and provide mutual support and protection.
While owning only a few belongings (3) and creating language to communicate (4) are important aspects of human development, their direct link to survival in cold environments is less critical compared to shelter and social cooperation. Communication can enhance group cooperation but is not as immediately vital as finding shelter and forming social groups for survival.
Therefore, the most necessary early human developments for survival in cold environments would primarily be finding shelter in caves and banding together in clan groups.