According to the definition of the periosteum,
The periosteum is a membrane that covers the outer surface of all bones, except at the joints of long bones.
When boys go through puberty their voices change and they start to grow hair on different area of their body such as their chest, face and pubic area. Also they will start to get acne
Commensalism is when one organism B. Benefits and the other is unaffected.
Vitamins are organic substances because you get your vitamin D from the sun and the sun is not artificial is it. So that is false