Chemical reactions can be recognized by the presence of heat, light, or gas formation. The ultimate outcome for any chemical reaction is the... a) change from solid to a liquid b) presence of sound c) formation of a new chemical substance

C.) formation of a new chemical substance.

relative humidity is a measure of the amount of moisture in the air relative to the total amount of moisture the air can hold.

so d

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