Which polymer has a $C-O-C$ linkage?

Write down the name of monomers,structure of polymer and uses for the following polymers.

Phenol is used in the manufacture of

Which of the following statements are correct?
$a$. Natural rubber becomes soft and sticky at high temperature.
$b$. Neoprene is a polymer of $2-$chloro$-1,3-$butadiene.
$c$. Nylon $6,6$ is a polyamide fibre.
$d$. Buna$-S$ is an example of a homopolymer.

Explain the process of vulcanization of rubber.

Which of the following is a copolymer obtained by condensation polymerization?