What book is this ? you can find the answer in the text
If a can remember it was answer D
Nomads were the peoples who use to move from place to place by following animal voyages and vegetable cycles to find food. Nomadic culture and society apparently important because they manifest non-progressive development. Basically, Nomads are divided into three categories a. nomadic hunter-gatherers b. pastoral nomads c. Trader nomads.
The technology of Nomadic pastoralism is mainly animal husbandry, horticultural by the use of agrarian technology. Normally, this practice includes a good deal of knowledge about animal husbandry and land transportation technology. Whereas Trader nomads involved in small trading activities from one place to other which includes the trade of crops and goods. As these nomads use to wander from one place to another they use to exchange the cultural pattern such as technology, goods, crops with the inhabitants of that areas. Such exchange also results in a transmission of disease from one zone to other with these nomads.
The main reason why United States was involved in Vietnam is that the United States believed in the so called Domino effect: that if one country becomes communist, others might become communist too. So they got involved to stop the spread of communism (option a)
