The Rigveda has 10 Mandalas ('books'). There is significant variation in the language and style between the family books (RV books 2–7), book 8, the "Soma Mandala" (RV 9), and the more recent books 1 and 10. The older books share many aspects of common Indo-Iranian religion, and is an important source for the reconstruction of earlier common Indo-European traditions. Especially RV 8 has striking similarity to the Avesta, containing allusions to Afghan Flora and Fauna, e.g. to camels ("" = Avestan "uštra"). Many of the central religious terms in Vedic Sanskrit have cognates in the religious vocabulary of other Indo-European languages ("deva": Latin "deus"; "hotar": Germanic "god"; "asura": Germanic "ansuz"; "yajna": Greek "hagios"; "brahman": Norse "Bragi" or perhaps Latin "flamen" etc.). In the Avesta, Asura (Ahura) is considered good and Devas (Daevas) are considered evil entities, quite the opposite of the Rig Veda.