The degree of crystallinity of which of the following is highest?

$A$ polymer $X$ is biodegradable and is obtained from the monomers $Y$ and $Z$. What are $Y$ and $Z$?

Identify the monomer of Teflon.

Given below are two statements:
Statement $I:$ Ethene at $333$ to $343 \ K$ and $6-7 \ atm$ pressure in the presence of $AlEt_3$ and $TiCl_4$ undergoes addition polymerization to give $LDP$.
Statement $II:$ Caprolactam at $533-543 \ K$ in $H_2O$ through step growth polymerizes to give Nylon-$6$.
In the light of the above Statements,choose the correct answer from the options given below:

Which of the following polymers has ethylene glycol as one of its monomer units?

Which of the following polymers is a urea-formaldehyde resin?