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.
Tornados occur when the cold air mixes with the hot air so spring is normally when very cold air kind of hits pretty warm air and the molecules have something kind of like a reaction:).Source(s): Minnesota :). kelsey Â· 4 years ago.Thumbs up.ornados occur when the cold air mixes with the hot air so spring is normally when very cold air kind of hits pretty warm air and the molecules have something kind of like a reaction:). Source(s): Minnesota :). kelsey Â· 4 years ago. Thumbs up.