Question 1 Yes, we believe there is an FFE. Factors such as vapour pressure and various partitioning coefficients obviously play a role, but extensive field data indicate that internal biological processes govern the physico-chemical properties of the plants and that these properties vary substantially during the year. Presently, we believe that the key factor that governs the physico-chemical properties of the plants, and hence the FFE, is the volatile compounds produced by the plants