Why do all maps label the Equator 0° latitude and the Prime Meridian 0° longitude?

How do hearths affect cultural diffusion? a. a hearth is the destination of cultural diffusion. b. a hearth divides a cultural region in two. c. a hearth is the beginning point of cultural diffusion. d. a hearth is the means of cultural diffusion. e. a hearth is the meeting point of two diffuse cultures.