Scientists studying Mars long thought the history of its crust was relatively simple. One reason for this is that geologic and climate data collected by a spacecraft showed that the crust was largely composed of basalt, likely as a result of intense volcanic activity that brought about a magma ocean, which then cooled to form the planet's surface. A study led by Valerie Payre focused on additional information--further analysis of data collected by the spacecraft and infrared wavelengths detected from Mars's surface--that revealed the presence of surprisingly high concentrations of silica in certain regions on Mars. Since a planetary surface that formed in a mostly basaltic environment would be unlikely to contain large amounts of silica, Payre concluded that ________

Which choice most logically completes the text?

Question

Scientists studying Mars long thought the history of its crust was relatively simple. One reason for this is that geologic and climate data collected by a spacecraft showed that the crust was largely composed of basalt, likely as a result of intense volcanic activity that brought about a magma ocean, which then cooled to form the planet's surface. A study led by Valerie Payre focused on additional information--further analysis of data collected by the spacecraft and infrared wavelengths detected from Mars's surface--that revealed the presence of surprisingly high concentrations of silica in certain regions on Mars. Since a planetary surface that formed in a mostly basaltic environment would be unlikely to contain large amounts of silica, Payre concluded that ________

Which choice most logically completes the text?

Accepted Answer

Mars's crust likely formed as a result of other major geological events in addition to the cooling of a magma ocean.

Answer

the information about silica concentrations collected by the spacecraft is likely more reliable than the silica information gleaned from infrared wavelengths detected from Mars's surface.

Answer

high silica concentrations on Mars likely formed from a different process than that which formed the crusts of other planets.

Answer

having a clearer understanding of the composition of Mars's crust and the processes by which it formed will provide more insight into how Earth's crust formed.