Multiple parts are variable in number and in structure, perhaps arising from such parts not having been closely specialised for any particular function, so that their modifications have not been closely checked by natural selection.
Organo anizkunak aldagarriak dira kopuruz eta egituraz, agian organo hauek funtzio konkretu baterako asko espezializatu ez direlako, eta halatan, hautespen naturalak ez die aldakuntzarik hertsiki eragotzi.