There are many verses about the connection between sin and death, as well as other consequences, but for now I'm just going to post this one, which clearly states that death came into the world because of sin. Please note that it says ALL sinned, which is what I've been trying to tell you, that even if the very first humans hadn't rebelled, it still would've been someone else.
I'll bold the pertinent parts:
"Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned" - Romans 5:12