Public Reporting Burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. The research performed under this agreement produced: (i) a procedure, based on deterministic and stochastic hybrid system reachability tools, for identifying parameters of different biological systems; (ii) a technique for identifying parameters for continuous state models of protein regulatory networks; (iii) new insights, provided by these tools, into the operation of the mechanisms behind Planar Cell Polarity in Drosophila wings, and into the survival analysis of Bacillus subtilis.