1. Which one of the following is not expected to occur on an H-R diagram during the lifetime of a single star?
(a) The star will move off the main sequence toward the upper right of the diagram.
(b) Low-mass stars will become white dwarfs and end up toward the lower left of the diagram.
(c) The star will move along the main sequence from one place to another.
(d) All of the above.
2. When can parallax be used to determine the approximate distance from the Earth to a star?
(a) Only during January and July.
(b) Only when the star's distance is relatively small.
(c) Only when the star's distance is relatively large.
(d) Only when the star appears to move directly toward or away from the Earth.
(e) Only when the star is the Sun.
(f) Always.
(g) Never.