recognizing and reacting to individuals based on group affiliation was probably a very important skill for early hunter–gatherers, whose survival often depended on quickly identifying others as potential friends or foes. this categorization was made primarily on the basis of

Sam and ben have discovered some strange animals living in the woods behind their house. ben is excited because he believes they are marsupials, an animal he's never observed in the wild before. his brother is sure it is not. what feature should the boys consider in deciding whether the animals are marsupials?

11. why do citizens have to register to vote?

What are the five traits of a civilization?