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Q23 past assessments of the brazilian rain forest

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Q23: Past assessments of the Brazilian rain forest have used satellite images to tally deforested areas, where farmers and ranchers have clear-cut and burned all the trees, but such work has not addressed either logging, which is the removal of only selected trees, as well as surface fires, burning down individual trees but do not denude the forest. 25
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A. which is the removal of only selected trees, as well as surface fires, burning B. which removes only selected trees, or surface fires that burn C. which removes only selected trees, along with surface fires that burn D. removing only selected trees, or surface fires, burning E. removing only selected trees, as well as surface fires that burn Answer: ------------------------------------------------------------------------------------------------------------ Q24: By sucking sap from the young twigs of the hemlock tree, tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop prematurely. ------------------------------------------------------------------------------------------------------------ Q25 to Q28: Recently biologists have been interested in a tide-associated periodic behavior displayed by Line the diatom Hantzschia virgata , a (5) microscopic golden-brown alga that inhabits that portion of a shoreline washed by tides (the intertidal zone). Diatoms of this species, sometimes called “commuter” diatoms, remain (10) burrowed in the sand during high tide, and emerge on the sand sur- face during the daytime low tide. Just before the sand is inundated by the rising tide, the diatoms burrow (15) again. Some scientists hypothesize that commuter diatoms know that it is low tide because they sense an environmental change, such as an alteration in temperature or a change (20) in pressure caused by tidal move- ment. However, when diatoms are 26
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observed under constant conditions in a laboratory, they still display periodic behavior, continuing to bur- (25) row on schedule for several weeks. This indicates that commuter diatoms, rather than relying on environmental cues to keep time, possess an inter- nal pacemaker or biological clock (30) that enables them to anticipate peri- odic changes in the environment. A commuter diatom has an unusu- ally accurate biological clock, a consequence of the unrelenting (35) environmental pressures to which it is subjected; any diatoms that do not burrow before the tide arrives are washed away.
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