This question is incomplete because of the absence of the graph. However, the independent variable of an experiment is the variable that is not affected by any other variable during the course of the experiment but is however intentionally or unintentionally predetermined by the researcher conducting the experiment. For example, in an experiment to determine the effect of age on blood pressure; age is the independent variable because the age class/groups of the individuals to be used can be determined by the researcher also the age cannot be affected by the pressure (the age of a person cannot change because of an increase/decrease in blood pressure).
Also, the control of an experiment is the variable/data in which other data in the same experiment are compared to. For example, in an experiment to determine the effect of a substance (such as sepin-1) on the growth of cancer cells (using a culture medium), the control can be the culture medium that was not given any substance or the culture medium that was given a pure substance of no effect like water. This means, in this control culture medium, the cancer cells will continue to grow normally while that growth will be compared with what is seen in the culture medium treated with sepin-1.
