Astronomy current events question: building blocks of life on Mars?

Astronomy 210L, spring semester 2013
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)

DC Agle and Dwayne Brown, "NASA Rover Finds Conditions Once Suited for Ancient Life on Mars," March 12, 2013
http://www.nasa.gov/mission_pages/msl/news/msl20130312.html

NASA's Mars rover Curiosity shows that ancient Mars could have supported living microbes by drilling into sedimentary rock and finding:
(A) DNA fragments.
(B) fossilized microorganisms.
(C) chemical building blocks of life.
(D) water-bearing crystals.
(E) air pockets.

Correct answer: (C)

Student responses
Sections 30678, 30679, 30680
(A) : 0 students
(B) : 6 students
(C) : 31 students
(D) : 11 students
(E) : 2 students