- (Topic 2)

Correct Answer:B

- (Topic 2)
An exercise ball is made from soft elastic thai has uniform thickness of 2 millimeters, and the interior of 1the ball is filled with air. The ball is in the shape of a sphere and has an exterior diameter of 65 centimeters. What is the radius of the interior of the ball, in millimeters?

Correct Answer:A

- (Topic 3)
What accounts for the low-lying. Hat surface of Mars's north? On Earth's surface, higher- and lower-lying areas have different types of onest: one. thin and dense, is pulled toward Earth's center more strongly by gravity, and the planet's water naturally comes to sit over it. creating oceans. The processes that generate this oceanic crust drive plate tectonics.
Is Mars's north similarly characterized by a sort of crust different from other areas of the
planet? Some researchers do see signs of tectonic activity surrounding the northern basin that suggest that it was created through the formation of new crust, like ocean basins on Earth. However. McGill points to northern bedrock structures that predate the features said to mark the start of the tectonic process. McGill instead believes that through some novel mechanism the ancient surface sank to its current depth as a single unit. This would explain why features around the basin's edge. which would have formed as the surface dropped, seem to be younger than structures at its floor.
The third possibility is that the northern lowlands result from impacts. Some researchers suggest they formed as a series of big overlapping impact craters. Others, arguing that the odds against such a pattern of impacts are large, postulate a single event—the impact of an object bigger than any asteroid the solar system now contains.
The passage implies that McGill points to certain "northern bedrock Structures? in order to

Correct Answer:B

- (Topic 3)
Scientists have long debated the exact timing of the lunar cataclysm, a period approximately 4 billion years ago when Earth and the Moon were pummeled with asteroids. A clue to this puzzle may come from spherules, millimeter-sized droplets of molten rock formed after au asteroid collides explosively with a planet. Upon impact, the asteroid vaporizes both itself and the target rock, producing a vapor plume that condenses into spherules. These form a layer preserved in rock, whose age can be estimated using radiometric dating. Scientists know of fourteen of these spherule layers scattered across Earth, but none dates to the theorized lunar cataclysm time period. Four layers, however, are from between 3.47 and 3.24 billion years ago. indicating perhaps a slow decline in collisions.
The primary purpose of the passage is to

Correct Answer:D

- (Topic 3)
Mathematicians have sometimes acknowledged that _____ is a requirement for creativity: for example. Poincare described explicitly a time when he experienced an insight after an incubation period, a period during which the unconscious mind was at work.

Correct Answer:C