Sickle cell anemia is caused by a mutation that changes one amino acid in hemoglobin. Describe how this change could affect the different levels of protein structure. *

The answer is ozone layer.

Where are they though?

It's either -limiting factors or -scarce resources but i'd go with my first answer since the food and water are abundant they really aren't scarce

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.