carat or gallon

UNIT
WordClue
ACRElitre - gallon, hectare - ?
FOODcarat - diamond, calorie - ?
INCHlitre - gallon, centemetre - ?
MILElitre - gallon, kilometre - ?
YARDlitre - gallon, metre - ?
LITREyard - metre, gallon - ?
METREgallon - litre, yard - ?
MOTORdiesel or stepping
ORDERfungus or stop-loss
PARTYRepublican or Conservative
POUNDlitre - gallon, kilogram - ?
POWERsolar or of will
RIVERNeva or Mekong
CALORIEdiamond - carat, food - ?
DIAMONDdioptre - glasses, carat - ?
DIOPTREdiamond - carat, glasses - ?
GLASSEScarat - diamond, dioptre - ?
KILOGRAMgallon - litre, pound - ?
KILOMETREgallon - litre, mile - ?
CENTEMETREgallon - litre, inch - ?
GLASSEScarat - diamond, dioptre - ?
SPICEcaraway or cumin