Question

in an experiment, 90 newborn flies are divided evenly into three separate groups and placed in boxes inside an incubator that is maintained at a constant temperature of 30°c. on a daily basis, the first group is given water containing 1 mg/ml of sugar; the second is given water containing 2 mg/ml of sugar; and the third is given water containing 3 mg/ml of sugar. after four weeks, the average length of the flies in each group is determined.
what should be the title of the line graph that displays data from this experiment?
a. concentration of sugar (mg/ml) vs. average length of fly (mm)
b. the effect of changing the concentration of sugar (mg/ml)
c. the proportion of flies in each of three experimental groups
d. average length of fly (mm) vs. concentration of sugar (mg/ml)

Explanation:

Step1: Identify the variables

The independent variable is the concentration of sugar (mg/mL) and the dependent variable is the average length of the fly (mm).

Step2: Analyze the format of a line - graph title

A line - graph title should show the relationship between the independent and dependent variables. The format “Independent variable vs. Dependent variable” is appropriate. Here, the concentration of sugar is the independent variable (it is being changed) and the average length of the fly is the dependent variable (it is being measured based on the change in sugar concentration).

Step3: Evaluate each option

• Option B: “The effect of changing the concentration of sugar (mg/mL)” does not mention the dependent variable (average length of fly), so it is incomplete.
• Option C: “The proportion of flies in each of three experimental groups” is not relevant to the variables (sugar concentration and fly length) measured in the experiment.
• Option D: The order of variables is wrong. The independent variable (concentration of sugar) should come first in the “vs.” format.

Answer:

A. Concentration of sugar (mg/mL) vs. average length of fly (mm)