what evidence was brought forth during the trial to support the indictments?

During the trial to support indictments, the tribunal retained the discretion to treat hearsay and other forms of evidence that are usually considered unreliable in the United States and Great Britain, as real evidence. This was different from the normal evidence that would be accepted at such tribunals. Decisions were made by a majority of vote of all the four judges.

just finished this it is b. centrifugal force

the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.