Final answer:
Neanderthals evolved certain physical traits such as increased blood supply to facial tissues, large nasal apertures, a stocky build, an occipital bun, and a shorter stature to adapt to cold climates, conserving heat and maintaining agility for hunting.
Step-by-step explanation:
Neandertal traits that evolved for adaptation to cold climates include an increased blood supply to facial tissues, large nasal apertures for humidifying and warming cold air, stocky builds to conserve heat, occipital buns potentially for musculature attachment leading to a stronger neck, and short stature to minimize surface area and retain body heat.
Neanderthals had large nasal cavities to warm and moisten air before it reached the lungs. Their occipital bun, robust musculature, and use of fire and tools were also significant in their survival in cold climates. A stocky build, including a barrel chest and shorter limbs, reduced heat loss while maintaining agility for hunting. Their short stature also lessened skin exposure to the cold environment, reducing the risk of frostbite and hypothermia.