$37-$ Give two examples for polymers used as: $($i$)$ elastomers $($ii$)$ rigid plastics

$($iii$)$ Fibers $($v$)$ Plastics or elastomers

$38-$ Explain the main characteristics giving one example for each type:

$($i$)$ Elastomers $($ii$)$ Plastics $($iii$)$ Fibers

$39-$ Compare between low density and high density poly ethylene