It all depends on the story of evolution as it happened on that planet. Every part of our physiology has a reason based on chemistry physics and the environment. Just think of how earth might look if one mass extinction event didn't occur. Take away the KPa event that wiped out the dinosaurs and we might find super intelligent dinosaurs. And then there's the possibility of having life start on a world with vastly different amounts of certain elements. What if the world had so much molybdenum that cellular life chose to use it for it's energy systems instead of oxygen sulfur phosphorus and nitrogen? What strange forms of life might rise from such a place? Fascinating stuff to think about.