Air tends to move from
a. the equator to the poles
b. conduction
c. cold air rising and warm air sinking
d. radiation

cold air rising and warm air sinking

Explanation:

Convection is well known in nature. During convection, warm particles rise above the surface while cooler particles sink below. Hence a convection current is set up.

Air moves by convection. Hot air rises and moves toward and is then replaced with cooler air. A typical application of convection in nature is land and sea breeze.

in chemistry, a solution’s concentration is how much of a dissolvable substance, known as a solute, is mixed with another substance, called the solvent. the standard formula is c = m/v, where c is the concentration, m is the mass of the solute dissolved, and v is the total volume