What event was considered to be the spark that lights fire of ww1?

Which product would have been most likely to have been traded in this area at this time?

1. what was the result of growing nationalism and pan-africanism on european-african relations? africans were encouraged to seek independence from europe. european colonialism grew and strengthened in africa. the change of power from european to african rule went smoothly. africans believed they could live peacefully with europeans.

Look at the graph. where p is price and q is quantity, what might cause a move from b to a?