What do you mean by unit?​

1 : a single thing, person, or group forming part of a whole There are 36 units in my apartment building. 2 : the least whole number : one. 3 : a fixed quantity (as of length, time, or value) used as a standard of measurement An inch is a unit of length.

Unit is the quantity of a constant magnitude which is used to measure the magnitudes of other quantities of the same nature.

The standard known quantity which is used to measure a physical quantities is known as unit.

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.​