The most striking feature of CAM plants is the formation of malic acid at

✅ Explanation: CAM (Crassulacean Acid Metabolism) plants have a unique adaptation to arid environments. They open their stomata at night to minimize water loss through transpiration. During the night, they take in carbon dioxide (CO2) and incorporate it into malic acid, which is stored in vacuoles. During the day, the stomata close, and the stored malic acid is broken down to release CO2 for photosynthesis. So, the formation of malic acid primarily occurs at night.