Research is designed to measure the association between variables that are not manipulated by the researcher.
a. cross-sectional
b. descriptive
c. correlational
d. basic

Option c. Correlational

Explanation:

Correlational research is basically a method of carrying out a research where an experiment can not be conducted and where a researcher has to figure out that whether the two variable are in association with each other and if these are related then in what way the association between these two exists without any manipulation from the researcher's end.

It seeks to understand, measure and make assessment of the relationship or  

association between these variables but can not find out if a variable is caused by the other variable.

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​