What is one of the major challenges faced by terrestrial organisms?

Terrestrial organisms face a significant challenge in reducing water loss due to their exposure to the atmosphere, which is typically drier than their aquatic counterparts. Unlike aquatic organisms, which are surrounded by water and can absorb it through their skin or gills, terrestrial animals must actively conserve water to prevent dehydration. Adaptations such as efficient kidneys that concentrate urine, specialized skin that minimizes evaporation, and behaviors like seeking shade or being active during cooler parts of the day are crucial for maintaining water balance. This challenge is paramount in many terrestrial environments, especially arid regions, where water availability can be a limiting factor for survival and reproduction.