Hi there! I believe the answer is:
D. An explanation of natural events that is well supported by scientific evidence
I hope this helps :)
Answer;
-Noble gases or Group 18 elements
Explanation;
A full valence shell is the most stable electron configuration. Group 18 elements or noble gases such as helium, neon, and argon, have a full outer, or valence, shell. Elements in other groups have partially-filled valence shells and gain or lose electrons to achieve a stable electron configuration.
They are extremely unreactive and do not form bonds with themselves. Solid helium is the the ultimate fine powder being monotomic.
The cell cycle, or cell-division cycle, is the series of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells.
The part of the Sun that you are observing when you see a blotchy appearance is the surface of the sun. This appearance is called granulation which is caused by the convection of the hot material inside the sun which go up and down the surface of the sun. Because of its sandy texture it is sometimes called lemon peel or rice grain.