Rap music first appeared in New York in the 1970's. Later, it spread to large cities with vibrant African-American populations -
such as Los Angeles, Oakland, Chicago and Detroit - without being absorbed by the smaller cities and rural areas in between. This type of spatial diffusion is called?
D. A large newspaper conducts a survey on its website asking readers whether the government should increase or decrease tariffs , its D because your scientific investigation has to be precise and clear
