A.The presence of life-forms far below the Earth’’s surface.B.The risk of infection from rare strains of bacteria.C.Fictional representations of a hidden underground world.D.The reliability of evidence collected by new drilling methods.
A.The presence of life-forms far below the Earth’’s surface.
B.The risk of infection from rare strains of bacteria.
C.Fictional representations of a hidden underground world.
D.The reliability of evidence collected by new drilling methods.