Explanation:

 Jet streams are relatively narrow bands of strong wind in the upper levels of the atmosphere. The winds blow from west to east in jet streams but the flow often shifts to the north and south. Jet streams follow the boundaries between hot and cold air.  Since these hot and cold air boundaries are most pronounced in winter, jet streams are the strongest for both the northern and southern hemisphere winters.

Second statement is incorrect as the jet streams are more meandering in the northern hemisphere, as the hot and cold fronts are more pronounced in the northern hemisphere. due to the differential heating of land and water.