Choose the correct option(s) from the following

• A

  Natural rubber is polyisoprene containing trans alkene units.
• Correct answer
  B

  Nylon- $6$ has amide linkages.
• C

  Cellulose has only $\alpha$ -D-glucose units that are joined by glycosidic linkages.
• Correct answer
  D

  Teflon prepared by heating tetrafluoroethene in presence of a persulphate catalyst at high pressure.

Solution

$\left(\mathrm{A}\right)$ Natural rubber is poly isoprene containing Cis stereo-chemistry alkene units.
$\left(\mathrm{B}\right)$ Nylon- $6$ has amide linkage, i.e., .
$\left(\mathrm{C}\right)$ Cellulose is a straight chain polysaccharide composed of $B\to$ Glucose units held together by $C_1-C_4$ glycosidic linkage
$\left(\mathrm{D}\right)$

Hence, the correct answer is options: 'B', 'D'.