Which polymer from the following is used as synthetic leather?

Which of the following statements are correct?
$(1)$ Biodegradable polymers can be converted into essential life substances after degradation.
$(2)$ Non-biodegradable polymers are active towards environmental processes.
$(3)$ Non-biodegradable polymers can be converted into essential life substances.
$(4)$ $PHBV$ is degraded by bacteria under environmental conditions.

$R$ is one of the monomers for the formation of a polymer called

Caprolactam is used for the manufacture of

The biodegradable polymer obtained by polymerization of glycine and aminocaproic acid is

$X$ is a polymer,which is mainly used for making unbreakable cups and laminated sheets. The monomers of $X$ are