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.

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.

i think that you are smart and you should fit for it out

it's diluted or concentrated

in a diluted solution, you can add a lot more solute but in concentrated only a little more can be added