Astronomy current events question: liquid water under Mars' south pole

Astronomy 210L, fall semester 2018
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!)

Roberto Orosei, Andrea Cicchetti, Dmitri Titov, and Markus Bauer, "Mars Express Detects Water Hidden under Planet's South Pole" (July 25, 2018)
esa.int/Our_Activities/Space_Science/Mars_Express/Mars_Express_detects_liquid_water_hidden_under_planet_s_south_pole

__________ observed by the European Space Agency's Mars Express spacecraft provide evidence of liquid water under Mars' south pole.
(A) Vapor plumes.
(B) Dark ice tunnels.
(C) Radar reflections.
(D) Gravitational fluctuations.
(E) Surface soil erosion.

Correct answer: (C)

Student responses
Sections 70178, 70186
(A) : 4 students
(B) : 1 student
(C) : 15 students
(D) : 0 students
(E) : 7 students