Here's a hypothesis for the duckweed experiment: “if duckweed is grown at pH 5, then it will grow at the same rate as when grown at pH 7, or normal pH, because it can tolerate mildly acidic environments.” Which elements should be controlled variables for this experiment? Check all that apply. environmental pH
timing of experiment
duckweed population
environmental light
amount of nutrients
environmental temperature

Aresearcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (tmv). the cell contents are left in a covered test tube overnight. the next day this mixture is sprayed on tobacco plants. we expect that the plants would ) develop some but not all of the symptoms of the tmv infectionb) develop the typical symptoms of tmv infectionc) not show any disease symptomsd) become infected, but the sap from these plants would be unable to infect other plants