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 Payré 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, Payré concluded that ______
Which choice most logically completes the text?
Choose 1 answer:
Choose 1 answer:
(Choice A) high silica concentrations on Mars likely formed from a different process than that which formed the crusts of other planets.
A
high silica concentrations on Mars likely formed from a different process than that which formed the crusts of other planets.
(Choice B) Mars’s crust likely formed as a result of other major geological events in addition to the cooling of a magma ocean.
B
Mars’s crust likely formed as a result of other major geological events in addition to the cooling of a magma ocean.
(Choice C) 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.
C
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.
(Choice D) 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.
D
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.

1. The text mentions that the crust of Mars was thought to be mainly composed of basalt due to intense volcanic activity and the cooling of a magma ocean.

2. A study led by Valerie Payré discovered high concentrations of silica in certain regions on Mars, which is unusual for a planetary surface formed in a basaltic environment.

3. Since a basaltic environment is unlikely to contain large amounts of silica, Payré concluded that the high silica concentrations on Mars likely formed from a different process compared to the formation of crusts on other planets.

4. This conclusion suggests that the presence of silica on Mars may have a unique origin or geological history, distinct from other planets.

Therefore, Choice A is the most logical completion of the text as it aligns with Payré's conclusion based on the data analysis of silica concentrations on Mars.