BioMart allows homology information to be exported as attributes, including the % Identity and '[Species Name] % Identity'. The % identity is the percentage of amino acids in the currently selected sequence that are identical in its homologue and '[Species Name] % Identity' is the percentage of amino acids in the homologue that are identical in the currently selected sequence. For example, if the species selected is arabidopsis, and the homologue is in maize, the query sequence is the arabidopsis protein and the target is the maize protein. % Identity in this case is the % of the arabidopsis protein identical to the maize protein, and "maize % Identity" is the % of the Maize protein identical to the arabidopsis protein. These % identities will only be the same if the length (number of amino acids) of the arabidopsis and maize proteins are the same.