Extreme weather e.g. snow and cold weather. Another main contributing factor is that many places have a long dry season.
The group on the periodic table that would have 0 electronegativity due to the fact that their valence shell is full, i.e, have a full octet would be the inert or noble gases. They have a total of 8 electrons in their valence shell and are thus inert and cannot strongly attract electrons toward itself, from neighbouring atom electrons as it does not need to.
Answer: Pigment.
Explanation: Our hair color is determined by two types of pigment, Eumelanins, and Pheomelanins. Which together produces all the natural hair colors we see every day with other people.
