How were sumerian communities called city states?

Ahumid tropical climate brings rain in the summer and drier weather in the winter to the malay archipelago.

The idea that depression is influenced by genetics, neurotransmitters, learned responses, thinking patterns, and socioeconomic status and culture represents the model of psychology.

When copernicus changed the way we think about the solar system, he did so not by discovering new information, but by looking differently at information already available. edward jenner's discovery of a smallpox vaccine occurred when he shifted his focus to disease prevention from the then more common emphasis on cure. history is replete with breakthroughs of this sort?