Question

how do roadway serve as a public facility

Answer 1

Well its not that only we you and me use the road its used by the whole world (the whole public)

So thats the reason road is a public favility

Answer 2

Unsaturated hydrocarbons are more reactive when compared to saturated hydrocarbons as in the unsaturated compounds we have double bonds(pi bonds) which are weak and can be easily cleaved by incoming group therefore increasing the reactivity. In saturated hydrocarbons only sigma bonds are present,these bonds are very strong and stable.