Astronomy quiz question: "ice giant" jovian planets

Astronomy 210 Quiz 7, fall semester 2012
Cuesta College, San Luis Obispo, CA

Uranus and Neptune are referred to as ice giants because they:
(A) are jovian planets located furthest from the sun.
(B) have prominent polar ice caps.
(C) are rich in liquid and solid forms of water.
(D) have icy rather than rocky moons.

Correct answer (highlight to unhide): (C)

While Uranus and Neptune are farthest from the sun, their atmospheres (still being primarily composed of hydrogen and helium) have a greater proportion of various forms of water than does Jupiter and Saturn.

Section 70158
Exam code: quiz07sEcn
(A) : 21 students
(B) : 6 students
(C) : 6 students
(D) : 1 student

Success level: 23% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33

Section 70160
Exam code: quiz07n0iC
(A) : 15 students
(B) : 4 students
(C) : 6 students
(D) : 0 students

Success level: 29% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33