Why encumber the system with unnecessary tubes and apparatus when functions can be combined.
Because then choking to death or the closure of the urethra due to the enlargement of the prostate gland wouldn't be a problem?
Of course, if God knew before hand that humans would deserve horrible painful deaths, then this is indeed pretty good designing.
Speaking personally, I find few things more awesome than contemplating this vast and majestic process of evolution, the ebb and flow of successive biotas through geological time. Creationists and others who cannot for ideological or religious reasons accept the fact of evolution miss out a great deal, and are left with a claustrophobic little universe in which nothing happens and nothing changes.
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M. Alan Kazlev