(Gen 2:17 KJV) But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.
So what happened "in the day that thou eatest"?
Both. The actual sin is spiritual death, separation of a relationship with God.
However, that sin resulted in condemnation to death, physical death. Satan took man captive through death and sin. Man sins because he is mortal as I Cor 15:56 states. We don't sin in the same manner as did Adam. Our flesh has become weak, and because it is susceptible to death it gives birth to all the vices that work against his fellow man. Decay, corruption and death became the end of God's creation. Man would simply be dissolved by death, dust to dust. Gen 3:19.
Christ is the solution by assuming the same nature that Satan captured, our human nature, and defeated death by his own death and resurrection, giving life to the world, Rom 5:18.
I explained this to you before, did you not understand it?