Which of the following polymers contains the $-CO-NH-$ linkage in it?

Consider the Assertion and Reason given below.
Assertion $(A):$ Ethene polymerized in the presence of Ziegler-Natta catalyst at high temperature and pressure is used to make buckets and dustbins.
Reason $(R):$ High density polymers are closely packed and are chemically inert.
Choose the correct answer from the following:

Which of the following is incorrectly matched?

Toluene diisocyanate $(TDI)$ is used in the synthesis of which polymer?

'Rayon' is

What is polythene? Write down its properties and types. Explain the preparation,properties,and uses of different types of polythene.