As preordained by the Fountain-head of Creation, the temple of the world hath been fashioned after the image and likeness of the human body. In fact each mirroreth forth the image of the other, wert thou but to observe with discerning eyes. By this is meant that even as the human body in this world, which is outwardly composed of different limbs and organs, is in reality a closely integrated, coherent entity, similarly the structure of the physical world is like unto a single being whose limbs and members are inseparably linked together.
Were one to observe with an eye that discovereth the realities of all things, it would become clear that the greatest relationship that bindeth the world of being together lieth in the range of created things themselves, and that co-operation, mutual aid and reciprocity are essential characteristics in the unified body of the world of being, inasmuch as all created things are closely related together and each is influenced by the other or deriveth benefit therefrom, either directly or indirectly.
Consider for instance how one group of created things constituteth the vegetable kingdom, and another the animal kingdom. Each of these two maketh use of certain elements in the air on which its own life dependeth, while each increaseth the quantity of such elements as are essential for the life of the other. In other words, the growth and development of the vegetable world is impossible without the existence of the animal kingdom, and the maintenance of animal life is inconceivable without the co-operation of the vegetable kingdom. Of like kind are the relationships that exist among all created things. Hence it was stated that co-operation and reciprocity are essential properties which are inherent in the unified system of the world of existence, and without which the entire creation would be reduced to nothingness. (‘Abdu’l-Baha, from a Tablet; Compilation on ‘Nature’, prepared by the Research Department of the Universal House of Justice)