Magnetic bacteria and/or their fossils are present in such immense numbers deep in the crust that they contribute significantly to the earth's magnetic field.
(Magnetic bacteria and/or their fossils; are; present in such immense numbers deep in the crust that they contribute significantly to the earth's magnetic field) (they; contribute significantly; to the earth's magnetic field)
Magnetic bacteria and/or their fossils they
are contribute significantly
present in such immense numbers deep in the crust that they contribute significantly to the earth's magnetic field
to the earth's magnetic field