Expansion Diffusion

The spread of a cultural element, item, group of people, disease, or phenomenon from one place to another is diffusion.

What is the term for the location where an idea, culture, belief, or item originated?

Which type of diffusion involves the physical movement of a culture or group of people from one place to another, often leading to the weakening or disappearance of the original point of origin?

The spread of fashion trends from major global cities to smaller settlements, or the popularity of a video game after a major social media influencer starts playing it, are examples of which type of diffusion?

When a global fast-food chain like McDonald's adapts its menu items to suit local tastes and cultural preferences in different countries, while maintaining its core brand concept, this is an example of what type of diffusion?