Why is system of currency exchange necessary for international trade?

a. nearly all world currencies are worthless on the world market.
b. those buying goods on the world market only accepted in gold and silver.
c. most goods bought on the international market must be bought and paid for using united states dollars only.
d. there must be a way to pay for goods purchased from countries with different types of currencies due to nationalism.
you for any answer that you provide! : d

Apopulation is a group of individuals of a single species existing together in an area. a population’s range, the area it occupies, changes over time. populations, in turn, may form a network, or metapopulation, connected by individuals that move from one group to another. within a population, the distribution of individuals can be random, uniform, or clumped, and the distribution is determined in part by the availability of resources. how might the geographic range of a species change if populations could not exchange individuals with each other? how would your answer depend on what type of metapopulation existed?

Which statement presents a counterclaim to james cross giblin's viewpoint? egyptian hieroglyphs provide information about the country's history, medicine, science, and laws. the rosetta stone allowed people to read ancient egyptian writing. learning how to read hieroglyphs is the best way to understand the ancient culture of the egyptians. digging up ancient egyptian tombs teaches us more about the way people lived than hieroglyphs do

Recall that in one condition of the experiment conducted by stasser and titus (1985) about student council president candidates, all group members had access to the same information, and that in another condition, members had unique information that other group members didn't know. in the second (unshared information) condition, the group made a worse decision than in the first (shared information) condition. this occurred because groups seldom can agree on who is most expert. focus discussion on the information that all members know. often ignore dissenting opinions. avoid differences of opinion, given conformity pressures.