An experimental study is conducted examining the relationship between drinking caffeine and reaction time. participants given caffeine by the experimenters in different amounts, and then are assessed on various tests of reaction time. in this study, the amount of caffeine that a participant drinks is the

24-karat gold is considered to be pure gold. 18-karat gold is considered to be about 75% gold. what is 18-karat gold considered a mixture rather than a pure substance? a) it has a variable composition of other elements and minerals. b) its color is different than pure gold. c) the gold atoms are not arranged in a repeating pattern. d) it can be melted and transformed into a different substance.

Which action allowed farming to be expand into west texas? a inventing a new plow b developing dry farming c increasing demand for cotton worldwide d declining of the cattle ranching industry

Which legal case forced the university of maryland to admit an african american student to its law school?