Theological necessity of the physical immortality of the first and the last Adam

Abstract

"Romans 5:12 states that "by one man sin entered into the world, and death by sin; and so death passed upon all men." If physical death is the penalty of sin, would a sinless Adam and Eve have lived on and on forever, never experiencing physical death? Would they not then have continued to multiply indefinitely in obedience to Gen 1:28, until the earth was not merely "filled" but veritably over- whelmed with their numbers? In such a situation what alternative could there be but unimaginable overcrowding?"