One question of sentence completion

deckardcain
Sat, 09 Apr 2011 13:46:49 +0000

“Register” has a meaning of indicating the measured result on a meter.
ex: The thermometer registered 130 degrees.

Maybe this interesting article would help you better understand the question.

[Barometers of environmental change - Community - Living - The Guardian](http://www.theguardian.pe.ca/Community/2010-03-18/article-1371596/Barometers-of-environmental-change/1)