What did Themistocles recognize about the Persians?

the answer is a glaciers carved a large valley that later flooded and became puget sound

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.

hello,

the steamboat is your answer.

it seems like its the only form of transportation on the choices.