Which Statement Is True

Multiple Choice

Which statement is true?

A) It is likely that collisions of comets brought water to ancient Earth.
B) Water is useful, but not essential, for life as we know it.
C) The first water on Earth was generated by metabolic activity of cyanobacteria.
D) As early Earth cooled and chemicals dissolved in the water, chemical reactions would not have occurred, because there was no oxygen.
E) There is no evidence that water has ever occurred on Mars.