 Leaving aside the question of just how this primary mover moves what it moves directly, the next phase in the unification of beings is the one in which the sublunary world is integrated with the already unified superlunary one studied by astronomy. This takes place in Λ.10. One obvious indication of this unification is the dependence of the reproductive cycles of plants and animals on the seasons, and their dependence, in turn, on the movements of the sun and moon (Λ.5, 1071a13–16). And beyond even this there is the unity of the natural world itself, which is manifested in the ways in which its inhabitants are adapted to each other: