What is happening in this diagram? 4 iterations of the following structure: 2 carbons double bonded to each other, each bonded to H above, the left C bonded to H below and the right to R below. The chain begins with an I and a dot. A curved arrow points from the dot to the space before the first structure above; curved arrows point left and right from the double bonds to the spaces before and after the structures. Arrow points to a long chain of carbons, I at the beginning of the chain. The carbons are all bonded to H above, and alternate bonding to H and R below. Polymers are forming large monomers. Monomers are forming large polymers. Polymers are breaking down into monomers. Monomers are breaking down into polymers.