Hi these structures would include the skin, nails, hair, glands, and nerves.
Hope this helped you.
I think it would be advantageous to observe mold colonies on an agar plate because one is able to observe colony structures, pigmentation, among others. Colony forming units are the individual colonies of bacteria,yeasts or mold. A colony of bacteria or yeast refers to a mass of individual cells of same organism, growing together.
Both a and b (it was an easy google search lol)