It is theoretically possible that bacteria developed on Mars early in its history and that some were carried to Earth by a meteorite. However, strains of bacteria from different planets would probably have substantial differences in protein structure that would persist over time, and no two bacterial strains on Earth are different enough to have arisen on different planets. So ________.
(A) Whether or not bacteria actually developed on Mars.
(B) Its likely it is that Martian bacteria were transported from Earth.
(C) Martian bacteria could have been carried to Earth by means other than meteorites.
(D) All bacteria now on Earth could have arisen from transported Martian bacteria.
(E) There could have been strains of bacteria that originated on Earth and later died out.
What would be the best option to complete the passage?
OA D
(A) Whether or not bacteria actually developed on Mars.
(B) Its likely it is that Martian bacteria were transported from Earth.
(C) Martian bacteria could have been carried to Earth by means other than meteorites.
(D) All bacteria now on Earth could have arisen from transported Martian bacteria.
(E) There could have been strains of bacteria that originated on Earth and later died out.
What would be the best option to complete the passage?
OA D
