Becquerel's discovery of radioactivity, and thereby radiometric dating,
not only indicated a much older age of the Earth than Lord Kelvin's thermal calculation of a "young Earth," only 20 million years, but providing the mechanism of extra heat as well which would keep Earth's core so warm even billions of years after Earth's creation.
A. not only indicated a much older age of the Earth than Lord Kelvin's thermal calculation of a "young Earth," only 20 million years, but providing the mechanism of extra heat as well which would keep
B. not only indicated a much older age of the Earth than did Lord Kelvin's thermal calculation of a "young Earth," only 20 million years, but also provided the mechanism of extra heat, which keeps
C. not only indicated a much older age of the Earth than Lord Kelvin's thermal calculation of a "young Earth," only 20 million years, but also to provide the mechanism of extra heat as well, keeping
D. not only indicated a much older age of the Earth than did Lord Kelvin's thermal calculation of a "young Earth," only 20 million years, but providing the mechanism of extra heat which would keep
E. not only indicated a much older age of the Earth than did Lord Kelvin's thermal calculation of a "young Earth," only 20 million years, but provided the mechanism of extra heat as well, keeping