Final answer:
Deserts are characterized by low annual precipitation, high evaporation rates, and extreme temperature variations. They are arid regions with little monthly variation in rainfall and lack of predictability in precipitation. Deserts have adaptations in plant and animal species to cope with the harsh conditions.
Step-by-step explanation:
Deserts are characterized by low annual precipitation, little monthly variation in precipitation, and a lack of predictability in rainfall. They have very dry conditions with high evaporation rates that typically exceed precipitation. Deserts can be hot during the day with soil surface temperatures above 60°C (140°F), but can also experience cold temperatures at night.
In terms of moisture, climates can be classified as arid (dry), semi-arid, humid (wet), or semi-humid. Deserts are considered arid because they have low annual precipitation of fewer than 30 cm (12 in). Subtropical deserts, such as the Sahara in northern Africa and the Namib in southwestern Africa, are dry because of high-pressure, dry air descending at those latitudes.
The low and unpredictable precipitation in deserts has led to adaptations in plant and animal species. Many plants are annuals that grow quickly and reproduce when rainfall occurs, then they die. Other plants have adaptations that conserve water, such as deep roots and water-storing stems. Desert animals exhibit adaptations like nocturnal behavior and burrowing to survive in the harsh environment.