Answer to practice problem 2 (Test 1)

2)  Planet E appears larger in the sky than planet F.  Which of these
    theories could account for that fact?
    (a) E is larger than F, and closer to Earth.
    (b) E is smaller than F, and closer to Earth.
    (c) E is larger than F, and farther from Earth.
    (d) E is smaller than F, and farther from Earth.

(a), (b), and (c) are correct. Planet E could appear larger either because it really is larger or because it is closer to us than planet F. (a) is certainly correct, because both factors would make E look larger. (d) is certainly wrong, because both factors would make E look smaller than F. (b) and (c) are also correct, because the question asks which theories could account for E appearing larger. If it is smaller than F, it can still appear larger if it is close enough; if it is farther away, then it can still appear larger if it is enough larger.