Before revision:  A central question is whether modern machine learning methods can be applied to construct predictive models based on large data sets drawn from complex, natural systems like cells and brains . In machine learning, the predictive power or generalizability of a model is determined by the statistics of training data .
After revision:  A central question is whether modern machine learning methods can be applied to construct predictive models based on large data sets drawn from complex, natural systems like cells and brains based on large data sets?