The answer is B, carbohydrates.
Carbohydrates are the first choice of the energy source of your body, they can be broken down into simple and soluble compounds such as glucose. These can be used by cells for respiration to generate energy for activities such as growth, movement, repair etc. Besides using for respiration, they are also capable of forming cell structures such as cellulose.
Oxygen, nitrogen, carbon, hydrogen NOT magnesium
Only one strand will be transcribed and the other servers as a coding stand. ... Without it, the single strand DNA with exposed nitrogenous bases is very unstable so two strands actually stabilise the structure.
