Why do the galvanized iron roofs houses become rusty?

Adistinctive characteristic of mammals that is not observed in other vertebrates is

3. in the fruit fly, recessive mutation brown, b, causes brown color of the eye and absence of red pigment. recessive mutation p of another independent gene causes purple color of the eye and absence of brown pigment. the cross of a brown-eyed female and purple-eyed male produced wild type eyes. what will be the colors and their ratio in f2?

I've created a synthetic cellular membrane that is made up of phospholipids, but contains no proteins. which of the types of movements across a membrane would not function with my synthetic membrane?