hectare - acre, kilogram - ?

POUND
List of words for the clue hectare - acre, kilogram - ? from the crossword:
YARD MILE METRE KILOMETRE INCH GALLON CENTEMETRE ARE AREA UNIT ROO LITER ROOD TONNES MASS TEACHER ACRES EEYORE ROODS
WordClue
ACREkilogram - pound, hectare - ?
INCHhectare - acre, centemetre - ?
MASSsecond - time, kilogram - ?
MILEhectare - acre, kilometre - ?
TIMEkilogram - mass, second - ?
UNITkilogram or hertz
YARDhectare - acre, metre - ?
LITREpound - kilogram, gallon - ?
METERmass - kilogram, distance - ?
METREacre - hectare, yard - ?
GALLONhectare - acre, litre - ?
SECONDmass - kilogram, time - ?
HECTAREpound - kilogram, acre - ?
DISTANCEkilogram - mass, meter - ?
KILOMETREacre - hectare, mile - ?
CENTEMETREacre - hectare, inch - ?
INCHhectare - acre, centemetre - ?
MILEhectare - acre, kilometre - ?