Astronomy quiz question: matter produced by past stars?

Astronomy 210 Quiz 7, fall semester 2017
Cuesta College, San Luis Obispo, CA

Another star, in the past produced the:
(A) hydrogen in red dwarfs.
(B) helium in the sun's core.
(C) iron in your blood.
(D) Milky Way's dark matter.
(E) (More than one of the above choices.)
(F) (None of the above choices.)

Correct answer (highlight to unhide): (C)

Stars produce metals (elements heavier than hydrogen and helium) in their cores during their giant/supergiant phases, up through type Ia/II supernovae explosions. Along with their unused hydrogen, these metals are then scattered into the interstellar medium, which are then incorporated into later generations of stars (or planets). Since iron is the only metal listed above, it is the only choice produced by a star in the past. (Dark matter is thought to have existed from the very early stages of the universe onwards, in order to facilitate the formation and maintain the structural integrity of galaxies.)

Section 70158
Exam code: quiz07Sl0p
(A) : 2 students
(B) : 4 students
(C) : 10 students
(D) : 0 student
(E) : 21 students
(F) : 4 students
(No response: 2 students)

Success level: 28% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.38

Section 70160
Exam code: quiz07ni4N
(A) : 3 students
(B) : 0 students
(C) : 12 students
(D) : 0 students
(E) : 11 students
(F) : 2 students

Success level: 47% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.43