How does the external nostrils help frogs survive?

External nostrils in frogs play a crucial role in their survival by allowing them to breathe while partially submerged in water. When a frog is in a resting position, it can keep its body underwater while its nostrils remain above the surface, enabling it to take in oxygen without fully emerging. This adaptation is vital for their aquatic lifestyle, helping them avoid predators and conserve energy. Additionally, external nostrils aid in detecting odors in their environment, which is important for finding food and mates.