Deoxyribonucleic acid or DNA is a molecule that contains the instructions an organism needs to develop, live and reproduce. These instructions are found inside every cell, and are passed down from parents to their children.ach nucleotide contains a phosphate group, a sugar group and a nitrogen base. The four types of nitrogen bases are adenine (A), thymine (T), guanine (G) and cytosine (C). The order of these bases is what determines DNA's instructions, or genetic code.
Hello, Dryness of scalp can be due to hormonal imbalance, poor health, poor hygiene, allergic hypersensitivity, lack of rest, emotional stress, excessive consumption of sugar, fat or starch, heredity predisposition and medical causes like eczema, atopic dermatitis or seborrheic dermatitis.
Eczema Causes. Doctors don't know exactly what causes eczema. The most common type of eczema -- atopic dermatitis -- resembles an allergy. But the skin irritation, which is more often seen in children rather than adults, is not an allergic reaction.The current thinking is that eczema is caused by a combination of factors that include: 1  Genetics.czema Causes. Doctors don't know exactly what causes eczema. The most common type of eczema -- atopic dermatitis -- resembles an allergy. But the skin irritation, which is more often seen in children rather than adults, is not an allergic reaction.