Class A (type D) CpG ODNs (CpG-A ODNs) contain a central palindromic phosphodiester (PO) CpG sequence and a PS-modified 3â poly-G tail. The poly G tails form intermolecular tetrads that result in high molecular weight ordered structures.
Why does a tornado form when cold and hot air meet? The collision of warm and cold air is not the direct cause of a tornado, nor is it absolutely necessary. When a cold air mass pushes into a warm air mass (this is called a câ¦old front) the warmer, less dense air is forced upwards.
Rating Newest Oldest. Best Answer: The most basic conditions to produce thunderstorms and tornadoes are cold dry air and warm moist air. The warm air rises through the cold air and forms clouds. The stronger the differences between air masses; the more likely that a thunderstorm will form. However, when the air masses are very different, super cell thunderstorms occur and can produce tornadoes. http://en.wikipedia.org/wiki/Thunderstor... http://www.nssl.noaa.gov/edu/safety/torn...