Is there a word for measuring "how easily change can happen or be made"?

If one word exists, I will call it X.

X would describe how easily change can happen or be made, in general. Example:

This building is made out of legos, so it has a high X, thus making it easy to make changes to it.

The wind today can be very weak or very strong. Either way, it’s gonna have high X.

Making a sculpture out of stone is hard. You can only take bits out of it and doing that is not very easy neither precise. The stone has low X.

I’d imagine X would be used in physics for example.