Pie charts showing the nodes (biological entities, left) and causal edges (causal relationships, right) contained in the Human Knowledge Assembly Model (KAM). Knowledge Assembly Models are collections of nodes (biological entities) and causal edges (causal relationships) and are used as substrates for Reverse Causal Reasoning (RCR). The number of nodes and causal edges contained in the Human KAM for each sub-category is shown in parentheses. These pie charts are a snapshot of the Human KAM as of August 18, 2010; the KAM is continually being expanded and refined. KAMs are also maintained for Mouse and Rat, and additional custom KAMs can also be created. Every KAM represents a subset of the global Selventa Knowledgebase.