12. jet streaks intensify mid-latitude cyclones by creating directly above the surface low pressure center.

a instability
b a region of divergence
c turbulent flow
d a shortwave

The correct answer is B: a region of divergence

Explanation:

Mid-latitude cyclones are low pressure systems that are formed through divergence (horizontal outflow of air) high in the atmosphere.

Jet streaks are segments of a jet stream (high-speed ribbons of air). They usually create a great amount of speed shear (the changing of wind direction and the increasing of wind speed). They can bring down cold air coming from the north into the southern parts of the country. As in low pressure centers air rises through convergence (horizontal inflow of air), the diverging air must be greater for the cyclone to intensify. For this reason, the low pressure center, now coupled with the jet streak, becomes stronger.