1.it is an experiment where the researcher manipulates one variable and controls the rest of the variables.
a.quantity
b.descriptive research
c.quantitative research
d.experimental research

2.it is a study designed to determine the relationship between variables from the same group of subjects
a.experimental research
b.descriptive research
c.correctional research
d.quantitative research

3.it aims to establish a cause-and-effect relationship between an independent and dependent variable and useful tool in situation where true experiment cannot be used for ethical or practical reasons
a.quasi-elemental research
b.descriptive research
c.correlational research
d.experimental research ​