Through one man sin entered the world, and death through sin, and thus death spread to all men because they had all sinned." Romans 5:12
This verse has been used to prove that Adam was responsible for sin and death.
From a Christian standpoint, this is true.
Did Adam really know the full effects of eating the forbidden fruit?
"In the day you positively eat from it, you will die." Genesis 2:17
This is quite a faith testing question for me so I'm going to have a go
Adam knew enough to exercise faith but didn't know the full awful effects. From a human standpoint, if he'd known we can say he wouldn't have sinned. We all say that don't we with hindsight.
God didn't tell Adam in advance because Adam was learning and exercising choice as we all must
I believe that Adam took responsibility after he'd sinned and accepted that the redeemer would come from his offspring, as we all must for ourselves. But Adam believed that Cain would fulfill that role. (it seems that we humans all have this sense of immediatecy)
thanks for raising such thought provoking questions
respectfully
bernadette