Complex sentence: Since the internal concentration of metabolites is not considered within a model it is possible that an FBA solution could contain metabolites at a concentration too high to be biologically acceptable: a problem that dynamic metabolic simulations would probably avoid.
Split into simpler sentences: Since the internal concentration of metabolites is not considered within a model. It is possible that an FBA solution could contain metabolites at a concentration too high to be biologically acceptable: a problem that dynamic metabolic simulations would probably avoid.