Which is the correct use of the word “emerged”?
west african kingdoms emerged to form one union.
trade emerged as a main source of income.
gold emerged from one merchant to another.
which merchant will best emerge the wealth?

The correct answer is: Trade emerged as a main source of income.

The verb "to emerge" means, in this scenario, becoming apparent, important. So it would mean that now, trade has become the main source of income.

Also, all the other sentences are not making the most appropriate use of the verb, being best substituted by other verbs.

the correct answer is b

hope i someone

roosevelt believed that in light of the country's recent military successes, it was unnecessary to use force to achieve foreign policy goals, so long as the military could threaten force. this belief, and his strategy of “speaking softly and carrying a big stick,” shaped much of roosevelt's foreign policy.