A cow is given a growth hormone and then compared to another cow that was not given a growth hormone. Both cows were weighed when they turned two years old. What is the independent variable and dependent variable?

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?