Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks

Most traditional human life in deserts is nomadic. It (35) ______ in hot deserts on finding water, and on following infrequent rains to (36) ______ grazing for livestock. In cold deserts, it depends on finding good hunting and fishing grounds, on sheltering from blizzards and winter (37) ______, and on storing enough food for winter. Permanent settlement in both kinds of deserts requires permanent water, food sources and adequate shelter, or the technology and energy sources to (38) ______ it.

Many deserts are flat and featureless, lacking landmarks, or composed of repeating landforms such as sand (39) ______ or the jumbled ice-fields of glaciers. Advanced skills or devices are required to navigate through such landscapes and (40) _____ travelers may die when supplies run (41) ______ after becoming lost. In addition, sandstorms or blizzards may cause disorientation in severely-reduced visibility.

The (42) ______ represented by wild animals in deserts has featured in explorers' accounts but does not cause higher (43) ______ of death than in other environments such as rainforests or savanna woodland, and generally does not affect human distribution. Defense against polar bears may be advisable in some areas of the Arctic. Precautions against snakes and scorpions in choosing (44) ______ at which to camp in some hot deserts should be taken.