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.

radiative zone

explanation    

radiative zone is the layer of the sun which energy is transferred away from the core by radiation. although, the core is the only part of the sun that produces an appreciable amount of heat through fusion. in fact, 99% of the energy produced by the sun takes place within 24% of the sun's radius.