Question

Question 39 2 pts Abotanist wants to study whether type of light affects plant growth. He gets ten identical plants and treats them all the same, except for the type of light they are under. He then records their growth in centimeters over the course of five weeks. In this scenario, plant growth is the independent variable control O experimental variable dependent variable O placebo

Answer 1

39. The independent variable is the variable that is controlled by the researcher and the dependent variable is the alterations that occur in response to independent variable. This dependent variable is the variable that depends on independent variable. In this experiment, the researcher altered the type of light that was exposed to the ten plants. Hence, type of light is independent variable. The effect of type of light was studied on plant growth. Hence, plant growth is the response to exposure to different types of light. Thus, plant growth is the dependent variable.

Controlled variable is the variable that is not altered by the researcher in the experiment. Hence, type of plant, any fertilizers used, duration of treatment, types of pots etc are the controlled variable as they are applied to all plants. Placebo is the treatment given to the negative control plants. Hence, these placebo plants will not be exposed to any specific type of light. It is the plants not subjected to independent variable- type of light. Experimental variable are the variables that are changed by the researcher during the experiment. Hence, the different light such as color of light (not used in placebo) etc used are experimental variables.

Right choice: dependent variable.