Öknar, or deserts, are arid regions characterized by very low precipitation, typically less than 250 millimeters (10 inches) annually. They often feature extreme temperatures, with scorching days and chilly nights. Common types of deserts include sand deserts, rocky deserts, and cold deserts, each with unique landscapes and ecosystems. Despite their harsh conditions, öknar are home to a variety of plants and animals adapted to survive with minimal water. Species such as cacti and succulents store water, while animals like camels and lizards have developed behaviors to cope with the heat and scarcity of resources.