Question

a factor scientists manipulate in an experiment
ethics controlled study
independent variable dependent variable

Explanation:

In an experiment, the independent variable is the factor that scientists deliberately manipulate to observe its effect on the dependent variable. Ethics relates to moral principles in research, a controlled study is a research design, and a dependent variable is what's measured in response to the independent variable. So the term matching "a factor scientists manipulate in an experiment" is independent variable.

Answer:

independent variable