I think the answer would be Vitamin D because the rest of the choices are characteristics of hair (cholesterol is what makes hair look/ appear oily; UV radiation is what hair protects your scalp from; and keratin [particularly dead keratin] is what your hair is made of) .... Whereas with vitamin D is what the skin produces and doesn't have any involvement with hair.
Hemoglobin
Durable.
HDL cholesterol is the good cholesterol because is flows in the bloodstream and removes harmful cholesterol from the areas in which it doesn't belong. If you have high HDL levels of cholesterol it will reduce your chance of getting heart disease.
Lipid is a term that is used to describe all types of fats. Cholesterol's structure falls under the category of lipids.
what's cholesterol's function as in the cell membrane
Cholesterol is a member of the alcohol group, as proven by its distinctive -ol suffix. It is thus an organic compound.
conduction
Cholesterol molecules are considered to be lipids since they are a class of steroids which are lipids. Cholesterol is hydrophobic due to its hydrocarbon composition; this is a commonality within lipids.
Electromagnetic radiation.
Lamellated granules, the rest are proteins or produce proteins found in the skin.
Yes, folic acid is otherwise known as vitamin B9. This vitamin is essential in the body and in some countries is added to foods such as cereals ad bread. It is also recommended that pregnant women take folic acid supplements.
Because insect wings are delicate. Most of the beetles (to which ladybirds belong) have a hard protective cover over their wings, to protect them from damage as the insect moves. This Keratin covering is tough and weatherproof.