To solve this problem, we need to understand the types of polymerization processes.$\newline$Polymers can be prepared by two main types of polymerization: addition polymerization and condensation polymerization.$\newline$Let's analyze each option:$\newline$• Option 1: Teflon$\newline$ - Teflon is prepared by the addition polymerization of tetrafluoroethylene (C_2F_4).$\newline$ - The process involves the repeated addition of monomer units without the loss of any small molecules.$\newline$ - Therefore, Teflon is formed by addition polymerization.$\newline$• Option 2: Nylon-66$\newline$ - Nylon-66 is prepared by condensation polymerization of hexamethylenediamine and adipic acid.$\newline$ - This process involves the elimination of water molecules.$\newline$ - Therefore, Nylon-66 is not formed by addition polymerization.$\newline$• Option 3: Novolac$\newline$ - Novolac is prepared by the condensation polymerization of phenol and formaldehyde.$\newline$ - This process involves the elimination of water molecules.$\newline$ - Therefore, Novolac is not formed by addition polymerization.$\newline$• Option 4: Dacron$\newline$ - Dacron, also known as polyethylene terephthalate (PET), is prepared by condensation polymerization of ethylene glycol and terephthalic acid.$\newline$ - This process involves the elimination of water molecules.$\newline$ - Therefore, Dacron is not formed by addition polymerization.$\newline$Based on the analysis, the correct answer is Option 1: Teflon, which is prepared by addition polymerization.