Which is not an example of laboratory research? a. compare tests of air quality in several metropolitan areas. b. identify biological mechanisms for the emergence of drug-resistant bacteria. c. use a food frequency questionnaire to examine dietary behaviors in a selected population group. d. develop a new vaccine.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.

true skin; another name for the dermis. lies directly beneath the epidermis and is often referred to as the true skin. outermost layer of epidermis, consisting of dead cells.