Although many aspects change with scale, there are certain invariant aspects to every system and stay consistent – like average heart rate for all people.
Scaling drug dosages from animals to people, or even to kids of different ages remains a challenge. Going from one organism to another rarely has identical interactions, and the scaling remains non linear even in the same organisms.
It remains difficult to determine truly invariant factors from simply slow changing ones.
The BMI index incorrectly because it takes weight increase by a factor of two, while it should use a factor of three – corresponding to the increase in volume.
If we wish to surpass physical limitations of growth, we must innovate by changing materials, design, or the environment surrounding the system.