Final answer:
Soaking hands under water for an extended period leads to pruning or wrinkling due to the nervous system's response, possibly an evolutionary adaptation for better grip in wet environments.
Step-by-step explanation:
Soaking under water for days will cause the hands to prune or wrinkle, which is a response to prolonged wetness. This occurs because the nervous system reacts to the stimulus of water and the skin's contact with a moist environment. This wrinkling is thought to be an adaptation that could have evolved to give our ancestors a better grip in wet conditions. Prolonged soaking can also soften the skin, potentially making it more susceptible to damage or infection if it is not cared for properly.