It A={x:x is a non negative integer and x² = x}, then how
many proper subset does A have?​

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.

It would be like the 70's song "it's raining men".

1.wear safety goggles when heating or mixing substances 2.tie back long hair when doing experiment in order to prevent from catching fire or dipping into chemicals accidentally 3.keep all exits and passages clear4.wear laboratory coats