Which polymer is used in controlled-release drug capsules?

Which of the following monomers is used in the synthesis of polythene?

$C_{3}H_{6}$,$C_{4}H_{8}$,and $C_{5}H_{10}$ belong to the same homologous series.
$(i)$ Define homologous series.
$(ii)$ Why are the melting and boiling points of $C_{5}H_{10}$ higher than $C_{4}H_{8}$?
$(iii)$ Arrange these hydrocarbons in order of increasing boiling points.

Which of the following is the correct representation of the electron dot structure of nitrogen $(N_2)$?

Intake of small quantity of methanol can be lethal. Comment.

Write true or false for the following statement:
Saturated hydrocarbons will generally give a clean flame,while unsaturated carbon compounds will give a yellow flame with lots of black smoke.