Pollution or Carbon Dioxide
Because the pole absorbs the heat quite readily, literally sucking the warmth from your tongue faster than your body can supply it. The saliva on your tongue then freezes (provided it is below freezing), with the resulting ice latching onto the flagpole and your very porous tongue.
Hope that helps you w/ ur question:)
The blue-white screen refers to a procedure of screening that allows for the brisk and convenient determination of recombinant bacteria in vector-based molecular cloning experiments. In the process, the DNA of interest is ligated into a vector. The blue colonies constitute of self-relegated plasmids that are devoid of DNA inserts obstructing the lac Z gene.
The white colonies contain bacteria that conduct plasmids, which possess the inserts of DNA fragments that obstruct the lac Z gene. Therefore, the researcher needs to sequence the plasmids of the white colonies prior to knowing which allele it constitutes.