[Agnes Heep]

I've always looked upon race as little more than an adaptation to climate. Asians, for example, have their eye folds, which limit light entering the pupil, and a greater mass to surface area ratio; this is the cold-weather type. It's just the opposite with blacks, whose dark skin filters UV rays and whose greater surface area to body mass (and hair texture) helps dissipate heat. Caucasians are the perfect temperate-climate type; nothing too extreme in any regard, which is great for the cool winters and warm summers of temperate zones. Of course human migration has landed many of each type in climates to which they're not physically adapted.

[Modernman]

Asians, for example, have their eye folds, which limit light entering the pupil, and a greater mass to surface area ratio; this is the cold-weather type.

Many parts of Asia are much warmer than Europe, so I'm not sure if this holds up.

[Cronos]

Caucasians are the perfect temperate-climate type; nothing too extreme in any regard, which is great for the cool winters and warm summers of temperate zones. Of course human migration has landed many of each type in climates to which they're not physically adapted.

Arabs, Persians, Indians. All Caucasians. All live in hot or tropical regions and have been doing so for millenia.