A biological species is defined as a 
 a) population or group of populations whose members have the potential to interbreed and produce fertile offspring. 
 b ) group of phenotypically indistinguishable organisms. 
 c ) group of organisms that are phenotypically similar and that share a high proportion of genes. 
 d ) population or group of geographically continuous populations whose members are phenotypically similar. e group of organisms that share an ancestral-descendant sequence.