The label for the concentration of the positive and negative transcription factors on the mRNA screen says "concentrations". Since there is only one thing being controlled, the term "concentration" seems more appropriate. I discussed this with @phet-steele and he agreed.
jbphet
commented
7 years ago
The label for the concentration of the positive and negative transcription factors on the mRNA screen says "concentrations". Since there is only one thing being controlled, the term "concentration" seems more appropriate. I discussed this with @phet-steele and he agreed.
Screenshot: