Doctors chase and sanborn are conducting an experiment on the effects of caffeine on memory. participants are randomly assigned to a caffeine or a no-caffeine group; their recall of items on a word list is later assessed. which pair below correctly names and identifies the variables in this experiment?

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.

Why do you think that wilson 14 point was not put into practice

How did geographical features create a civilization in china