The concept of internal human stability which is also a central concept of human physiology which you're talking about/asking a question about would be homeostasis. By a homeostatis we're talking about a very narrow interval of functioning in which people function best and have optimal working efficiency.
It was once beleived that the earth was flat. :) Hope it helps
White dwarf
Option 3.
<u>Explanation:</u>
White dwarf are very old in existence in the world. The white dwarfs are at least about twelve to thirteen billions years old in existence. These are only slightly younger than the universe itself.
Thus these white dwarfs provide a clear idea about how old the universe is and since when it has come into existence itself. Although not exact but some what idea can be made that it is about more than thirteen billion years old and came into existence back then.
That would be 0.42? Unless your asking something different
