The movement of substances (as by diffusion) across a cell membrane without the expenditure of energy.
Smoking has been statistically identified as a <em><u>causative</u></em> element in the development of cancers of the lung, tongue, esophagus, and stomach.
It's certainly not a <em>prevention</em> in any way.
Answer:
the growth rate of each of the plants/ the relative humidity inside each terrarium