A population of rattlesnakes lives on a desert island. Some members of this population have a unique adaptation which protects them form parasites that reside in the sand. The allele for this special adaptation is recessive. You count all the snakes on the island and find that there are 120 snakes, 42 of which do not have the adaptation to protect against the parasite. What is the frequency of carries ( i.e., heterozygous individuals who lack the adaptation but carrier the recessive allele for the adaptation) for this trait in the population?