Arthur reads an article describing an experiment to test the effects of caffeine on the reaction time of humans—how long it took them to respond to a particular signal. in the experiment, the subjects' reaction times were measured, then they were divided into three groups. one group was given a high dose of caffeine. the second group was given a medium dose of caffeine. the third group was given a sugar pill that had no caffeine. after waiting 45 min for the caffeine to take effect, the reaction times were measured again. in the experiment arthur read about, what was the outcome variable (dependent variable)? a. the change in reaction times for each person b. the amount of caffeine given to each person c. the amount of time the caffeine was given to take effect d. the type of signal each person responded to

A. the change in reaction times for each person

A. the change in reaction times for each person

Explanation:

In an experiment the dependent or experimental variable is the one which changes because of the impact of changes on the independent variable. The independent variable is the one which can be changed or manipulated in an experiment. It exerts it's effects over the dependent variable.

The coffee here is the independent variable. The third group with sugar pill and no coffee can be considered as control group. The change in the reaction times for each person is the dependent variable because it changes due to the intake of coffee.

-first use of geothermal energy occurred more than 10,000 years ago in north america by american paleo-indians

-the first industrial use of geothermal energy began near pisa, italy in late 18th century

-in 1904, italian scientist piero ginori conti invented the first geothermal electric power plant in which steam was used to generate the power

-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

-however, in 1946 first ground-source geothermal heat pump installed at commonwealth building in portland, oregon

-during the 1960’s, pacific gas and electric began operation of first large scale geothermal power plant in san francisco, producing 11 megawatts

-in 1973, when oil crisis began many countries began looking for renewable energy sources and by 1980’s geothermal heat pumps (ghp) started gaining popularity in order to reduce heating and cooling costs

-as effect of climate change started showing results, governments of various countries joined hands to fight against it, for which kyoto protocol was signed in japan in 1997, laid out emission targets for rich countries and required that they transfer funds and technology to developing countries, 184 countries have ratified it

hope this