Sara wanted to perform a scientific experiment relating the effect of ultraviolet (UV) light on the survival rate of microscopic protists in pond water. She went to a local pond and collected a large bucket of pond water, then poured 500 milliliters of the pond water into each of two identical glass jars. She viewed a small sample of the pond water under a compound light microscope to verify that the water contained multiple species of microscopic protozoa. She was also able to get a rough count of the organisms in her sample using a special microscope slide. To set up her experiment Sara took one of the glass jars with pond water and protists, labeled it “100”, and placed it 10 centimeters under a lamp that transmits 100% UV light. The other jar, she labeled “O” and placed it 10 centimeters under a lamp that transmits 0% UV light. After the pond water/protist mixture in both jars was exposed to the lights for 8 hours, she collected samples from both jars. She used the same procedure as before and made a 2nd count of the microorganisms to compare to her first count.
12. If Sara were to graph her data using a bar graph, what should her axes be labeled?