Final answer:
The correct choices are a) among, a) between, b) among, b) among.
Step-by-step explanation:
The correct answers are:
- a) among
- a) between
- b) among
- b) among
The word 'among' is used when referring to three or more people or things. In the first sentence, there can be multiple collectors and dealers, so 'among' is the correct choice. In the second sentence, 'mankind' represents a group, so again, 'among' is appropriate. In the third and fourth sentences, 'between' is used because they refer to specific individuals or things.
Learn more about Parts of Speech