Why is it that a 5-year-old can't pedal a bike?

A 5-year-old may not be able to pedal a bike because they may not have developed the necessary coordination, strength, and balance required to pedal effectively. Their motor skills and muscle strength are still developing at this age, making it challenging for them to coordinate the movement of pedaling a bike. With practice and time, most children are able to learn how to pedal a bike as they grow older and their physical abilities improve.