You are a researcher studying the effects of "Compound X" on the soil microorganism Azotobacter vinelandii. You add "Compound X" to a flask of A. vinelandii with a concentration of 1x106 CFU/mL. After 5 hours, you assess the concentration of A. vinelandii in the sample and it is 1x106 CFU/mL. What term best defines "Compound X"?

Tooth enamel consists mainly of the mineral calcium hydroxyapatite, ca_10(po_4)_6(oh)_2. trace elements in teeth of archaeological specimens provide anthropologist with clues about diet and diseases of ancient people. students at hamline university measured strontium in enamel from extracted wisdom teeth by atomic absorption spectroscopy. solutions with a constant total volume of 10.0 ml contained 0.726 mg of dissolved tooth enamel plus variable concentrations of added sr. added sr find the concentration of sr in the 10 ml sample solution in parts per billion = ng/ml. find the concentration of sr in tooth enamel in parts per million = mu g/g.