The one or more additional sensors are for sensing, for example, a piece of {HEAD ~ environmental information} in {TAIL ~ the immediate vicinity} of the hydration sensor 
in
The one or more additional sensors are for sensing , for example , a piece of { HEAD ~ environmental information } in { TAIL ~ the immediate vicinity } of the hydration sensor
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH