In the text is a photograph that appears to show four identical galaxies arranged as a cross. What are we really seeing?
A) four galaxies that are nearly identical because they were born at about the same time
B) four images of a single background galaxy, created by the gravitational lens of a massive foreground galaxy or cluster
C) a large galaxy with four central masses that glow brightly
D) a picture taken with a poorly made telescope, so that a single large object appears as four fuzzy dots
Question 2
At the Mars Pathfinder landing site, the surrounding rocks are scattered and stacked against each other. This suggests that the spacecraft landed in
A) an area of explosive volcanic activity
B) an ancient floodplain
C) an area subjected to wind erosion
D) the debris from a giant impact
Acromegaly in one individual from a pair of identical twins.
Irregular Galaxies
Microtubules: EM of cilia cross section
A radiator may be either a down-flow or a cross-flow type.
Capital’s Share of Income in a Cross-Section of Countries
Breeding garden pea plants (Pisum sativum), which can self-fertilize or cross-fertilize.