Final answer:
One manifestation of nationalism is the call to 'buy our country's products only', which is a form of economic nationalism. Nationalism can exist in any country regardless of its economic status.
Step-by-step explanation:
Nationalism is a political ideology that promotes the interests of a nation over international concerns and advocates for the uniqueness and superiority of one's own country. One manifestation of national feelings is the call to 'buy our country's products only', which is a form of economic nationalism. This shows a sense of national pride and a desire to protect domestic industries. It is not true that nationalist feelings are not prevalent in economically prosperous countries, as nationalism can exist in any country regardless of its economic status.