Fill in the Blanks The origin of plasticsOnline version Technologies for spanish speakers by Miriam Cano Cano 1 origin coal carbon petroleum resins chemical raw Natural polymer synthetic monomers Synthetic Plastics are materials made up of long molecules ( ) which are a combination of and hydrogen atoms . A set of many monomers forms a . Depending on their they can be : . - plastics , obtained directly from materials found in nature , such as rubber or . . - plastics made by processes from raw materials as , and natural gas . Most of plastics we use are .