Astronomy current events question: comet 67P Churyumov-Gerasimenko's "neck"

Astronomy 210L, fall semester 2015
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!)

Emily Lakdawalla, "How the Duck Got Its Neck: Rapid Temperature Changes from Self-Shadowing May Explain 67P's Unusual Activity and Shape" (September 11, 2015)
planetary.org/blogs/emily-lakdawalla/2015/09110855-how-the-duck-got-its-neck.html

Computer modeling of __________ may explain how comet Churyumov-Gerasimenko's "neck" developed over time.
(A) rapid temperature changes.
(B) random collisions.
(C) rotation rates.
(D) gravitational fields.
(E) seismic instability.

Correct answer: (A)

Student responses
Sections 70178, 70186
(A) : 22 students
(B) : 2 students
(C) : 1 student
(D) : 3 students
(E) : 2 students