A bird’s feathers would seem to be a (i)_____ design for protecting a bird from attack by microscopic organisms. They create a warm, moist space next to the skin that could be an ideal incubator for spores. Wild birds rarely (ii)_____ skin diseases, however. The chemicals in the sebum include an array of antibacterial and antifungal agents that allow the bird’s skin to (iii)_____.
答案：C,D,G