Silver and Gold belong to a special group of metals known as the native metals. They are found naturally on their own and not in combined form in rocks.
These metals are found uncombined because they are unreactive.
They prefer to alloy with themselves.
Calcium and magnesium on the other hand are reactive metals.
The unreactivity of these metals makes them uncombined in nature.
B is the correct answer. The exosphere is the outermost region of the atmosphere the gradually merges out into space. The water cycle does not occur within this region.
