Question

how do conditions in the united states change when the jet stream moves south?
a. the daylight lasts longer.
b. it gets colder.
c. it gets windier.
d. it gets warmer.

Explanation:

Jet streams are fast - flowing, narrow air currents in the atmosphere. When the jet stream moves south in the United States, it often brings in colder air masses from the north. Daylight duration is mainly related to the Earth's tilt and its position in its orbit around the Sun, not the jet stream's southward movement. While wind is associated with jet streams, the key and most direct impact of a southward - moving jet stream in the US context (in terms of the options given) is the introduction of colder air. Warmer air would be more likely if the jet stream moved in a different pattern (e.g., if it were bringing in air from the south in a more significant way, but that's not the case when it moves south in the typical sense for the US where the southward movement often relates to the polar jet stream bringing cold air).

Answer:

B. It gets colder.