Professor partridge has 9 seven-year-olds and 9 nine-year-olds study a set of pictures. he then asks the participants to verbally describe as many different pictures as possible. in this experiment, the independent variable is

Professor partridge has 9 seven-year-old and 9 nine-year-old study a set of pictures. He then asks the participants to verbally describe as many different pictures as possible. in this experiment, the independent variable is the AGE.

An experimental variable is referred to independent variable and variable quantity  is referred to dependent variable.
The difference between the dependent and independent variable is that the independent variable is not affected by any other variable,usually time.
Whereas,dependent variable totally depends upon the independent variable and changes according to the change in other variable.

Ifound this on google “separation of powers. a fundamental principle of the united states government, whereby powers and responsibilities are divided among the legislative branch, executive branch, and judicial branch.” i hope this you for what your looking for