What is an example of excretion in mammals?

In mammals urine is expelled through the urethra which is part of the excretory system in unicellular organisms waste products are discharged directly through the surface of the cell

Many archeologists and anthropologists disagree with dr. thorne's view.  thorne strongly believes that what many calls "homo erectus"  was in fact  homo sapiens,  and that they migrated out of africa almost 2 million years ago and dispersed throughout europe and asia. that's way different  from what scientists have always believed about the evolution of the species.