What reaction takes place when palm-oil is added to potash and foam are observed?

Explanation

Colonial economy focused on export crops: cocoa (West), palm oil (East), groundnuts and cotton (North), rubber, tin. Production oriented toward European industrial needs, not local consumption.

Infrastructure (railways, ports, roads) connected production areas to ports, not regions to each other. Currency replaced barter; taxation forced Nigerians into cash economy and wage labor.

Effects: neglect of food crops, dependence on imported manufactures, regional economic disparities, destruction of local industries, and economic structures that persist today.