Final answer:
The most important issue when using a single bone to estimate height is understanding the growth and function of bones, specifically long bones like the femur, which grow from their epiphyseal plates and provide attachment sites for muscles.
Step-by-step explanation:
When there is only one bone to work with to determine human height, the most important issue is the relationship between the size and shape of the bone to its function in the body. Bones like the femur, which is a long bone with a central shaft and two rounded ends, are critical for such estimates because they grow from the ends, or the epiphyses, where a growth plate or epiphyseal line is present. This growth plate is indicative of a bone's ongoing development and ossification. Premature closure of the epiphyseal plate can lead to a short stature. Additionally, the shape of a bone, as evidenced by the size of bony landmarks for muscle attachments, can relate to the strength of the muscles and thus reflect the overall size and strength of a bone structure, which indirectly informs about height.