【单选题】According to a recent theory, Archean-age gold-quartz vein systems were formed over two billion years ago from magmatic fluids that originated from molten granitelike bodies deep beneath the surface o...
A.
advocating a return to an older methodology
B.
explaining the importance of a recent theory
C.
enumerating differences between two widely used methods
D.
describing events leading to a discovery
E.
challenging the assumptions on which a theory is based