Copy and complete the following paragraph using the options given in brackets :
Alkenes are a homologous series of (i) ............... (saturated/unsaturated) hydrocarbons characterised by the general formula (ii) ............ (`C_(n)H_(2n+2)// C_(n)H_(2n))`. Alkenes undergo (iii) ................. (addition/substitution) reactions and also undergo (iv) .... (hydrogenation / dehydrogenation) to form alkanes.

Explanation

(i) unsaturated (ii) `C_(n)H_(2n)` (iii) addition (iv) hydrogenation