You are so dense.
The nature of Adam, as GOD created him, not only had the capacity to disobey GOD, but did disobey GOD.
The very same nature that GOD created him as, is the very same nature that disobeyed (unless you incorrectly think that GOD changed Adam's nature before he disobeyed).
The nature of man can still disobey GOD, so nothing has changed in that regard.
Exactly, and the law God gave Adam was given for the exact same reason the law is given to all men...whether that law be in our conscience or written down....it was to bring us to a realization that we are lost without God's direct intervention in our lives. We are to look to Him for our very existance. That's what faith is.