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.
A cold front would likely be a front that would produce hail and tornadoes in an area because cold fronts are different than warm fronts. Cold fronts are usually fronts that c â¦ ause storms and if they have the right recipe it could produce damaging winds, hail and sometimes if it's very strong, tornadoes.ornadoes frequently form along cold fronts and dry lines.  Occasionally they may form along warm fronts. Some tornadoes form  from thunderstorms not associated with any fro â¦ nts.