You know the story of how Adam landed us in the dilemma we're in - first sin, then death, and no one exempt from either sin or death.
That sin disturbed relations with God in everything and everyone, but the extent of the disturbance was not clear until God spelled it out in detail to Moses. So death, this huge abyss separating us from God, dominated the landscape from Adam to Moses.
Even those who didn't sin precisely as Adam did by disobeying a specific command of God still had to experience this termination of life, this separation from God. But Adam, who got us into this, also points ahead to the One who will get us out of it.