Question

the polar jet stream is stronger in the
a winter.
b summer.

Explanation:

The Polar Jet Stream is a fast - flowing air current in the upper atmosphere. In winter, there is a greater temperature contrast between the polar regions and the mid - latitudes. This temperature contrast drives stronger winds in the Polar Jet Stream. In summer, the temperature gradient is smaller, resulting in a weaker jet stream.

Answer:

A. winter