Answer:
B) The variable scientists observe for changes
Explanation:
The dependent variable is the one that changes due to the independent variable.
The independent variable is one that scientists can modify and then observe how the dependent variable changes. This dependent variable may not be the same in every experiment and also may not be constant during the experiment (which discards the options A and D), those things can happen but is not the definition of a dependent varible.
The answer is B) The variable scientists observe for changes
Because the dependent variable cannot be modified directly by the scientist, since as its name says it depends on other factors in the experiment, so the dependent variable is the one observed to analyze the changes occurred.
