GRE Free Practice Test

- (Topic 3)
Instances of "galactic cannibalism"—mergers in which large galaxies completely consume smaller ones—may be fairly common. Tidal forces produced by the Milky Way's powerful gravity, for example, appear to be dismantling and engulfing a dwarf galaxy in the constellation Sagittarius, producing large clumps and streamers of stars connecting the two galaxies. Astronomers have also observed two dense clusters of stars and gas at the heart of the Andromeda galaxy, an apparent "double nucleus" that may contain the remnant of a cannibalized dwarf galaxy. But this Twin-lobed appearance could also be created by two parts of a single nucleus bisected by a lane of dust. Scientists believe that only about 25 percent of such apparent double nuclei actually represent galactic cannibalism. Many of the rest result from the illusion of proximity that occurs when objects at different distances appear along the same line of sight: others consist of debris from galactic "collisions." in which one galaxy has passed through another without merging, causing waves of new star formation.
According to the passage, a true double nucleus may be produced by the

1. A. collision of two dwarf galaxies
2. B. incorporation of a dwarf galaxy into a larger galaxy
3. C. merging of two galaxies of approximately equal size
4. D. separation of a single nucleus into two parts by a lane of dust
5. E. waves of new star formation resulting from an instance of galactic cannibalism

Correct Answer: D

- (Topic 3)
Given the _____ of archival materials related to her subject, it is not surprising that the author is unable to
marshal much detailed documentary evidence to support some of her claims.

1. A. diversity
2. B. paucity
3. C. accessibility
4. D. orderliness
5. E. profusion

Correct Answer: B

- (Topic 3)
One reason researchers have long believed that Mars never enjoyed an extensive period of warm and wet climate is that much of the surface not covered by wind-borne dust appears to be composed of unweathered material If water flowed for an extended period, researchers reasoned, it should have altered and weathered the volcanic minerals, creating clays or other oxidized, hydrated phases (minerals that incorporate water molecules in their crystal structure).
It turns out. though, that the scientists were not looking closely enough. New high- resolution mapping data and close-up surface studies have revealed clays and other hydrated minerals in many regions The clay deposits are scattered all over, in ancient volcanic surfaces and heavily cratered highland regions, some of which have apparently been exposed by erosion only recently.
It can be inferred from the passage that the author would agree with which of the following statements regarding the reasoning discussed in the highlighted sentence?

1. A. It is based on an underestimation of the extent to which flowing water would alter volcanic materials on Mars
2. B. It provides the basis for an explanation of why water on Mars has been difficult to find until recentlyC It correctly identifies a consequence of water flowing on the Martian surface.
3. C. It results in a new understanding of how water and volcanic materials interact on Mars.
4. D. It fails to take into account the impact of wind-borne dust on the Martian surface

Correct Answer: C

- (Topic 3)
One of the remarkable things about (i) _____ is that it can seem so (li) _____ : many of the issues about which people (iii) _____ seem, to the nonzealot. to be gray and ambiguous at the core.

1. A. erudition
2. B. duplicity
3. C. conviction
4. D. benign
5. E. self-serving
6. F. unreasonable
7. G. feel absolute certainty
8. H. fail to educate themselves
9. I. find themselves puzzled

Correct Answer: AFH

- (Topic 2)
A car service charges S5 for the first mile of a trip and S2 for each additional mile or part thereof. If the car service charges SI01 for an //-mile trip, where // is an integer, what is the value of n ?

1. A. 47
2. B. 48
3. C. 49
4. D. 50
5. E. 51

Correct Answer: B