Minerals

can be solids, liquids, or gases
are made from the remains of plants and animals
must have a homogeneous chemical composition
are organic and naturally occurring

The biggest component / ingredient of summer time smog is

What is the rule relating the ratio of marginal utility to prices of two goods at the optimal choice? explain why, if this rule does not hold, the choice cannot be utility-maximizing.

Pj conducts an experimental study on the effects of soft music during high stakes science testing. he randomly assigns students at the school. in one condition he does not provide music for testing while in the other group he does provide the music. he administers a pretest at the beginning of the year and a posttest at the end of the year. pj’s design is best described as a: a.static group comparisonb. pretest-posttest control group designc.control-group-time-series designd. nonrandomized control-group pretest-posttest design