GMAT Critical Reasoning (CR) | Re: Museums that house Renaissance oil paintings typically store

Hi Experts,

Can you suggest my flaw while dissecting below argument:
Museums that house Renaissance oil paintings typically store them in environments that are carefully kept within narrow margins of temperature and humidity to inhibit any deterioration.

This is a fact

Laboratory tests have shown that the kind of oil paint used in these paintings actually adjusts to climatic changes quite well.

This is a fact because of - lab tests have ....

If, as some museum directors believe, paint is