A river flows from the farmer's field into two streams.

From one stream a sidestream very occasionally trickles into the mouths of men but most of this stream becomes a rapidly rushing river flowing to factories who process and put it into pretty packages.  This stream flows into global supermarkets to be displayed and sold to man.

Another stream flows into the barn and into the mouths of animals owned by man.  That stream stays there dammed-up, but only for a while.  When the stream has fattened man's animals the animals flow into a stream that flows into the mouths of men.  

Need we discuss subsequent streams?

...Or the rivers inside the body of man?