Need help pleeaasse

Which german count invented the zeppelin

(20+ points) (will mark brainliest) which of the following sections represent state-level courts?

One drawback of voluntary trade is that it a. requires two groups to use a common language b. can make one group dependent upon another for necessary goods c. doesn't occur unless there is a shortage of goods for at least one group d. forces groups to rely on themselves to produce all the goods they need