A scientist being interested in adding to our general knowledge about oxygen would probably call his approach ______.

A．classified knowledge
B．the study of unrelated fields
C．the study of unrelated subjects
D．an attempt to explain natural phenomena

A．In science, it is not difficult to distinguish fact from fiction.
B．Today few people have any notions of the meaning of science.
C．Practical-minded people can understand the meaning and objectives of pure science.
D．Scientists engaged in theoretical research should not be blamed for ignoring the practical side of their discoveries.