The amount of sunlight reaching Earth’s surface appears to be growing. The phenomenon, which some dub "global brightening," (1) scientists with a puzzle. If the (2) is real and global, how long will it last and what are the consequences for climate change, the planet’s water cycle, and other (3) that draw energy from sunlight (4) , the answer might seem obvious: More sunlight reaching the ground in a warming world means that temperatures will get warmer (5) . Not so fast, some researchers say. Additional warming would be certain (6) nothing else in the climate system changes. And the climate system is (7) static. Some combinations of changes could reinforce the heating; others could (8) it. Unraveling these interactions and forecasting their course require an accurate accounting of the sunlight reaching the surface and the (9) the surface sends skyward. Moreover, researchers say, measurements of
A. ongoing
B. outgoing
C. incoming
D. upcoming
Scientists who believe cell phones are dangerous have been throwing out hypotheses to explain away the negative results. Maybe something about the (34) animals raised their rates of cancer or sperm problems, so (35) the exposed animals didn’t seem to be harmed. Maybe the studies should have used pulsed, (36) radiation rather than a continuous beam, the better to (37) the way we actually use mobile phones. Maybe it matters (38) the lab animals are zapped (39) in a device like a Ferris wheel or while (40) around in cages. On the other hand, if these details do (41) , maybe that in itself is significant.
Scientists who (42) claims that cell-phone radiation is causing an epidemic of brain cancer (43) that there isn’t any mechanism. (44) textbook biophysics, only radiation that has enough energy to ionize molecules—that is, knock off electrons—can (45)
A. communication
B. distribution
C. permission
D. radiation
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