Controls are defined as ___.
A) variables scientists observe for changes
B) things that change during an experiment
C) variables that are changed by the scientist
D) things that are kept constant during an experiment

During an experiment, readings for blood pressure in a persons body were found to be constant . however , when he measured by a different blood pressure cuff , the readings differed by 15 points for each reading. this difference indicates that the results are

24. how are vaccines used to keep people healthy?

Dr. arenas is a scientist who has been trying to determine if increasing pressure will increase the sound that occurs when two chemicals explode. it measures the volume of the sound that occurs at the minimum pressure at which the explosion will occur. it then increases the pressure and measures the volume of the explosions that occur. what kind of investigation is the scientist conducting?