A student reads that nanosilver particles are used in cosmetics to allow nutrients to penetrate deeper into the skin. When the cosmetics are washed off, the nanosilver particles can enter freshwater ecosystems. These particles may decrease survival in many aquatic organisms. The student determines that Daphnia magna, a tiny freshwater crustacean widely found in North America, might make a good test subject for an experiment.
Which statement below is the most likely testable hypothesis based on the information provided?
A. When the concentration of nanosilver particles in water and the temperature of water are both increased, the population of Daphnia magna will decrease.
B. When the concentration of nanosilver particles in water and the temperature of water are both increased, the population of Daphnia magna will decrease.
C. When the concentration of nanosilver particles in water is increased, the population of Daphnia magna will adapt to new conditions and become a new species.
D. When the concentration of nanosilver particles in water is decreased, the population of aquatic organisms that feed on Daphnia magna will increase.

The statement below that is the most likely testable hypothesis based on the information provided is that when there is an increase in the concentration of nanosilver particles in water, the population of Daphnia magna will decrease.

Since we are informed that the particles may decrease survival in many aquatic organisms, it simply means that an increase in the particles in water will bring about the decrease in the Daphnia magna, which is the tiny freshwater crustacean.