Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Jet streams are fast-moving air currents high in the troposphere. They are also the result of unequal heating of the atmosphere. Jet streams circle the planet, mainly from west to east. The strongest jet streams are the polar jets. The northern polar jet is shown in Figure below . Answer: jet streams
Output:
What is the term for the fast-moving air currents high in the troposphere?