The harmless scarlet kingsnake has scales in a coloration and pattern resembling the scales of the dangerous coral snake.  the scarlet kingsnake is using  to avoid predation

a harmless animal the imitates another dangerous animal or plant is using Batesian Mimicry to avoid predatation.

The scarlet kingsnake is using Batesian Mimicry to avoid predation.

Explanation:

The coral snake has a coloration that warns its predators about its poisonous condition. The harmless scarlet kingsnake  is an imitating snake, which has the same colors rings of the coral snake, but is harmless, has no poison.  With this strategy they benefit because predators confuse them with venomous snakes and prefer not to eat them.  

According to some experiments, it has been proven that this condition only benefits the snake scarlet kingsnake. when it coexists in the same territory with the coral snake. This concept is called Batesian Mimicry.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".