Fill in each numbered blank with one suitable word or phrase.
Most traditional human life in deserts is nomadic. It (Question 41) ______ in hot deserts on finding water, and on following infrequent rains to (Question 42) _____ grazing for livestock. In cold deserts, it depends on finding good hunting and fishing grounds, on sheltering from blizzards and winter (Question 43) _____ , 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 (Question 44) ____ it.
Many deserts are flat and featureless, lacking landmarks, or composed of repeating landforms such as sand (Question 45) _______ or the jumbled ice-fields of glaciers. Advanced skills or devices are required to navigate aeuen such landscapes and (Question 46) travelers may die when supplies run (Question 47) _____ after becoming lost. In addition, sandstorms or blizzards may cause disorientation in severely-reduced visibility.
The (Question 48) _____ represented by wild animals in deserts has featured in explorers’ accounts but does not cause higher (Question 49) _____ 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 (Question 50) _____ at which to camp in some hot deserts should be taken.
