Abarrier to pathogens is provided by a. melanin. b. collagen. c. sebum. d. keratin.

Answer;

Keratin

Explanation;The skin contains the protein keratin, which resists physical entry into cells. Keratin helps to adhere cells to each other and to form a protective layer on the outside of the skin. In epithelial cells, keratin proteins inside the cell attach to proteins called desmosomes on the surface.Keratin makes our skin tough and provides us with much-needed protection from microorganisms, physical harm, and chemical irritation.

Brownies are good but they're messier than cookies. sugar cookies are also fun and more versatile to decorate. especially cut out cookies.

Because without physical activity, the body has extra "energy" if you will, and so when it is time for bed you are not tired, so you end up staying up all night. also there is probably an effect on your internal clock, which messes with your melatonin production which goes hand in hand with your sleep cycle