Hair is made of a tough protein called keratin. A hair follicle anchors each hair into the skin. The hair bulb forms the base of the hair follicle. In the hair bulb, living cells divide and grow to build the hair shaft. Blood vessels nourish the cells in the hair bulb, and deliver hormones that modify hair growth and structure at different times of life.
Phylum definition, Biology. the primary subdivision of a taxonomic kingdom, grouping together all classes of organisms that have the same body plan. See more. Dictionary.com
What is the meaning of sub phylum and phylum? A phylum is a group of animals that are directly drawn from a kingdom. A sub-phylum is a phylum that is slightly more accurate for a group of animals but is not a class.