A. SUFFER B. RESIST C. TOLERATE D. COMPLAINVII. READ THE PASSAGE A...

65. A. suffer B. resist C. tolerate D. ComplainVII. Read the passage and choose the best optionBirds that feed in flocks commonly retire together into roosts. The reason for roostingcommunally are not always obvious, but there are some likely benefits. In winter especially, it isimportant for birds to keep warm at night and conserve precious food reserves. One way to dothis is to find a sheltered roost. (line5) Solitary roosters shelter in dense vegetation or enter a cavity- horned larks dig holes in theground and ptarmigan burrow into snow banks-but the effect of sheltering is magnified by severalbirds huddling together in the roosts, as wrens, swifts, brown creepers, bluebirds, and anis do.Body contact reduces the surface area exposed to the cold air, so the birds keep each other warm.Two kinglets huddling together were found to reduce their heat losses by a quarter, and threeother saved (line 10) a third of their heat.The second possible benefit of communal roosts is that the act as “information centers.”During the day, parties of birds will have spread out to forage over a very large area. When theyreturn in the evening some will fed well, but others may have found little to eat. Someinvestigators have observed that when the birds set out again next morning, those birds that didnot feed well on (line15) the previous day appear to follow those that did. The behavior ofcommon and lesser kestrels may illustrate different feeding behaviors of similar birds withdifferent roosting habits. The common kestrel hunts vertebrate animals in a small, familiarhunting ground, whereas the very similar lesser kestrel feeds on insects over a large area. Thecommon kestrel roosts and hunts alone, but the lesser kestrel roosts and hunts in flocks, possiblyso one bird can learn from others where to (line20) find insect swarms.Finally, there is safety in numbers at communal roosts since there will always be a fewbirds awake at any given moment to give the alarm. But this increased protection is partiallycounteracted by the fact that mass roosts attract predators and are especially vulnerable if they areon the ground. Even those in trees can be attacked by birds of prey. The birds on the edge are atgreatest risk since (line 25) predators find it easier to catch small birds perching at the margins ofthe roost.