Final answer:
The defining characteristic of deserts is low precipitation.
Step-by-step explanation:
The defining characteristic of deserts is low precipitation. While high temperatures are common in many deserts, they are not the defining characteristic. Deserts can be found in cold regions as well. Lizards and cacti are examples of the flora and fauna that can be found in certain deserts, but they are not the defining characteristic. The lack of rainfall is what distinguishes deserts from other ecosystems.
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