One of the reasons why Nigeria is a mono-economy is because of her _______

A mono-economy is an economy relying on one major export or natural resources to bring most
of the currency into the country.
Nigeria is dependent on crude oil. Before now, agriculture and mining were the primary drivers of
Nigeria’s economy but these has been abandoned since the 70’s as a result of the discovery of oil.
Nigeria is now a mono-economic country that is, now relies solely on crude oil as her major source
of revenue.