I'm pretty confident the answer to your question is drought.
Hope this helps!
<span>Depending on the specifics of the culture, the gesture of a smile might not be recognized by tribe members. The bearing of teeth as done when one smiles, might be seen as an aggressive maneuver as seen in the animal kingdom.</span>
It is not an economic activity - it's linguistic in nature, not economic.
It is not linguistics either - linguistics is a scientific discipline.
It's also not a culture region - this would be a kind of region, and a region is not the same as spread of culture.
The correct answer is "a) cultural diffusion.
Early Roman alphabet is the answer.
