How do meteorologists use isotherms and isobars?

a. to identity high- and low-pressure systems
b. to identify areas of high and low water vapor
c. to differentiate between seasons
d. to provide estimates for the amount of direct sunlight received

A. To identity high- and low-pressure systems

Explanation:

Isotherms are imaginary line joining the places which received by the equal amount of temperature. Isotherms are regular in southern hemisphere and irregular manner in northern hemisphere because of preponderance of land in northern hemisphere. Isobars are imaginary line joining the places which received by the equal amount of pressure. Isotherm and Isobars are measured and it revealed the data about the temperature, pressure, direction of moving wind, precipitation and so on.