Final answer:
The two main jet streams in the Northern and Southern Hemispheres are the polar jet and subtropical jet. These jet streams affect weather patterns and can influence airplane travel, dictating their velocity relative to Earth.
Step-by-step explanation:
The correct answer to the student's question regarding the two main jet streams in both the Northern and Southern Hemispheres is A. a polar jet and a subtropical jet. Jet streams are fast flowing, narrow air currents found in the atmospheres of some planets, including Earth. The polar jet stream occurs near the poles at a latitude of about 60° North and South, while the subtropical jet stream is found closer to the equator, around 30° North and South latitude.
These jet streams play a significant role in determining weather patterns by directing the movement of air masses and influencing global precipitation. For example, the subtropical jet stream can affect the global belt of dry air masses and low precipitation at about 30° N and 30° S latitude. Additionally, jet streams can have profound effects on airplane travel, altering the velocity of airplanes relative to the Earth when flying within these fast-moving currents of air.