Well aliens are like mysteries on Sci-Fi. Aliens aren't humans or just beings that are different from us. When you're saying the thickness, I am assuming about the body of the alien is full of hard and rusty skin that is not like ours. Hope this helped!!! >.< If not I am sorry....just didn't understand what you were getting to at. I am sorry.
C.) Alien thickness is mainly affected by temperature. The greater thickness at lower temperatures may be used as a way to stay warmer in colder weather.
