The Corn Belt of the United States, the great maize-growing region, is centred on which states?

The correct answer is B, Sweden. Kiruna lies in Swedish Lapland, inside the Arctic Circle, and works a high-grade magnetite deposit of the Baltic Shield. Its ore is carried by rail to Narvik in Norway, an ice-free port warmed by the North Atlantic Drift, and to Lulea on the Gulf of Bothnia.

Option A, Norway, is only the outlet: Narvik handles Kiruna's ore but the mine is not Norwegian. Option C, Finland, shares the same shield and has copper, nickel and chromium mines, but no deposit of this fame. Option D, Denmark, is built of young sedimentary rock and has no metallic mining worth the name. The useful habit here is to link the ore to the shield it sits in, which is why northern Sweden, the Canadian Shield and Western Australia all appear in iron ore questions.

The correct answer is C, Saudi Arabia. Ghawar, discovered in 1948 in the eastern province of the kingdom, has been the largest conventional oil field known anywhere, and it is the field most often named in exams along with Safaniya, the biggest offshore field, also Saudi.

Option A, Iraq, has the great Kirkuk and Rumaila fields, and Rumaila is among the largest in the world, but not the largest. Option B, Iran, has Ahvaz, Marun and Gachsaran in the Zagros foothills. Option D, Kuwait, has Burgan, which is usually named as the second largest conventional field and therefore the most tempting wrong answer. All four countries draw their oil from the same great sedimentary basin of West Asia, formed from the sediments of the ancient Tethys Sea.

The correct answer is A, copper in Chile. Chuquicamata, in the Atacama Desert of northern Chile, is one of the largest open-pit copper mines in the world, and Escondida, in the same desert, is the other name to remember. The copper lies in the porphyry deposits of the Andes, which have made Chile the leading copper country for decades.

Option B is wrong because South African gold comes from the Witwatersrand basin, not from Chuquicamata. Option C names Bolivian tin, which comes from the Oruro and Potosi districts of the Bolivian plateau. Option D names Canadian nickel, which comes from Sudbury in Ontario and Thompson in Manitoba. The other great copper region to keep with Chile is the Central African Copperbelt of Katanga in the Democratic Republic of the Congo and the Zambian towns beside it.

The correct answer is B, gold. The Witwatersrand basin near Johannesburg has produced a large share of all the gold ever mined, from conglomerate reefs that dip deep underground, and the city of Johannesburg itself grew out of the gold rush of 1886.

Option A, diamond, is the wrong mineral for this place but the right one for Kimberley, also in South Africa, where the volcanic pipe gave its name to kimberlite rock, and for Mirny in the Russian republic of Yakutia. Option C, copper, belongs to Chile and to the Central African Copperbelt. Option D, tin, belongs to the South-East Asian belt through Malaysia, Thailand and Indonesia and to Bolivia. South Africa should be remembered for gold at Witwatersrand, diamonds at Kimberley and platinum and chromium in the Bushveld Complex.

The correct answer is B, Osaka. Osaka, in the Kansai industrial region, became the leading cotton textile centre of Japan, helped by a humid climate suited to spinning, a good harbour, cheap labour drawn from the countryside and a large home market, and the comparison with Manchester in England, the original Cottonopolis, is standard in textbooks.

Option A, Tokyo, with Yokohama, is the heart of the Kanto region and is known for engineering, printing, electronics and consumer goods rather than for cotton. Option C, Nagoya, is the centre of the Chukyo region and of the automobile and aircraft industries, and also of pottery. Option D, Yokohama, is the port and shipbuilding city of the Tokyo region. Only Osaka carries the Manchester comparison, just as Ahmedabad is called the Manchester of India.