Question

burning of insense stick can be smell from a distance why

Answer 1

hey mate this is so because of diffusion of insence stick gas molecules and air molecules. this diffusion increase with increase in temp
and decrease with decrease in temperature.

Answer 2

well, Burning of incense stick can be smell from a distance because when its temperature is high means its hot so its kinetic energy increases as matter have a property that the moment of particles will increase due to raise in temperature. Henceforth it happens due to phenomenon of diffusion.