Expansion diffusion is best described as:

• A. Spread of a trait that weakens in its origin
• B. Spread of a cultural trait while remaining strong in its area of origin and expanding to new areas
• C. Diffusion only through media
• D. Diffusion only by migration

Answer: (B)

Expansion diffusion describes how a cultural trait spreads outward from its place of origin while that origin remains strong and continues to influence others. The trait is adopted in new areas, but the original source still maintains its presence and impact. That combination—outward spread with an enduring, influential origin—is what defines expansion diffusion.

Spreading while weakening at the origin isn’t expansion diffusion, because the source loses influence rather than staying strong. Limiting diffusion to media ignores other pathways that can carry ideas, such as person-to-person contact, trade, or cultural exchange. Diffusion is also not restricted to migration; ideas can spread without people moving at all.