why is a chemically sensitive person not able to build an immunity to perfume?

what does "immunity" mean?

5 answers

See the second definition.

http://dictionary.reference.com/browse/immunity
i understand what immunity means now, but i still don't know how to answer this question.
http://txeh.org/What%20Is%20Chemical%20Sensitivity.htm
yeah like i know what chemical sensitivity is but i just don't undertand what the question is asking
I don't know how to simplify this question any further. Sorry.