How do cacti prevent water loss in the desert?

Cacti prevent water loss through adaptations such as thick, waxy skin and small, spiny leaves. Their skin reduces evaporation, while spines minimise surface area and deter herbivores. Cacti also open their stomata at night to reduce water loss during photosynthesis, a process called CAM (Crassulacean Acid Metabolism). These features enable cacti to survive and thrive in arid environments.