One important features of the vibrant US economy of the 1920s was mass production. A well-known pioneer of mass production was the car manufacturer Henry Ford. He adapted the assembly line production to his new car plant in Detroit.
The assembly line production forced workers to repeat a single task mechanically and continuously - such as fitting a particular part to the car - at a pace dictated by the conveyor belt. This was a way of increasing the output per worker by speeding up the pace of work.
Standing in front of conveyor belt no workers could afford to delay the motions, take a break, or even have a friendly word with a workmate. As a result, Henry Ford's cars came off the assembly line at three-minute intervals, a speed much faster than that achieved by previous methods. The T-model Ford was the world's first mass-produced car.
Mass production reduced the cost of good and this resulted in mass consumption.

The shikaripuri shroffs and Nattukottai Chettiars of India were amongst the many groups of bankers and traders who financed export agriculture in Central and Southeast Asia, using either their own funds or those borrowed from European banks.
They had a sophisticated system to transfer money over large distances, and even developed indigenous forms of corporate organisation.
India traders and moneylenders also followed European colonisers into Africa. The Hyderabadi Sindhi traders, however, ventured beyond European colonies and established flourishing emporia at busy ports worldwide. From the 1860s, they began selling local and imported curios to tourists whose numbers were beginning to swell, thanks to the development of safe and comfortable passengers vessels.

Stanley was a journalist and explorer sent by the New York Herald to find Livingston, a missionary and explorer who had been in Africa for several years. Like other European and American explorers of the time, Sir Stanley also went with arms, mobilised local hunters, warrior and labourers to help him, fought with local tribes, investigated African terrain, and mapped different region. These explorations helped the conquest of Africa.

Two examples of impact of technology on food availability
(i) The technique of cold storage and use of refrigerated ships boosted the export of perishable foods over long distances. Meat exported from America, Australia and New Zealand could be sent to Europe where meat was not available easily or cheaply.
(ii) Faster railways, larger ships and lighter wagons enabled cheaper and quicker movement of perishable foodstuffs from far away farms to their final markets. Now the poor in Europe could add meat (even butter and egg) to their daily diet.

(i) Since wages were low in China, they became attractive destinations for investment by foreign MNCs competing to capture world markets.(ii) The relocation of industry to low-wage countries stimulated world trade and capital flows.
(iii) In the last two decades the world's economic geography has been. transformed as countries such as India, China and Brazil have undergone rapid economic transformation.

The global transfer of disease in the pre-modern world led to the colonisation of the Americas in the following ways
(i) The Portuguese and the Spanish had a strong army. But along with these, germs and viruses helped them in conquering parts of Americas.
(ii) As Americas was isolated earlier, the original inhabitants had no immunity against the germs and viruses present in Europe.
(iii) The diseases once introduced, spread very fast. The diseases, like smallpox affected whole communities that were paving the way for the conquest of the colonisers.
(iv) The germs were more dangerous as compared to guns and fire arms because guns could be bought or captured, but there was no way to escape from these diseases.

The causes of the Great Depression were
(i) Conditions Created by War The Great Depression was the result of war. There was an immense industrial expansion due to the increased demand of goods supplied to the army, during the period of the First World War. After the war, the demand for these goods suddenly dropped. So, there was no demand in many industries. There was also a large fall in the agricultural prices due to reduced demand.
(ii) Over Production in Agriculture Agricultural over production was another major factor responsible for the depression. This was made worse by falling agricultural prices.
As prices fell and agricultural incomes declined, the farmers tried to increase the production. They tried to bring a larger volume of produce to the market to maintain their overall income. This act pushed down the prices of farm produce further.
(iii) Shortage of Loans In the mid-1920s, many countries financed their investments through loans from the USA.
While it was often very easy to raise loans in the USA during the boom period, lenders in the USA panicked at the first sign of trouble. Countries that depend crucially on US loans, now faced an acute crisis.
(iv) Collapse of Banking System With the fall in prices and the prospect of a depression i.e. banks in the USA slashed domestic lending and some stopped bank loans, thousands of banks went bankrupt and were forced to close down. Factories closed, leading to unemployment, which further aggravated the crises. The US banking system collapsed.
(v) Large-scale Unemployment Farm could not sell their harvests, which led to businesses collapse. As a result, large scale unemployment occurred.