1. Note that this term is in the subset of terms that should not be used for direct gene product annotation. Instead, select a child term or, if no appropriate child term exists, please request a new term. Direct annotations to this term may be amended during annotation reviews. 2. While a broader definition of behavior encompassing plants and single cell organisms would be justified on the basis of some usage (see PMID:20160973 for discussion), GO uses a tight definition that limits behavior to animals and to responses involving the nervous system, excluding plant responses that GO classifies under development, and responses of unicellular organisms that has general classifications for covering the responses of cells in multicellular organisms (e.g. cell chemotaxis).