Mark expands the Primal Blueprint Podcast by recording select Mark's Daily Apple posts for your listening pleasure!Although research is young, we are learning that the critters living on our skin, who number in the billions per centimeter of skin, are supposed to be there. And even though we don’t know exactly all they’re doing, we know this…(These Mark's Daily Apple articles were written by Mark Sisson, and are narrated by Brock Armstrong)