The answer is:
For the farmers own needs
This skin is known as the body membrane
Advantages of using solar energy are pollution-free, noise-free, on installation it produces free energy, clean and renewable. Disadvantages include high cost, energy dependent on sunlight exposure, power stations are expensive to build and devices powered by solar energy cannot be used at night
Hydrogen as in hydrocarbons
nitrogen as in cyanides
sulphur as in carbon di sulphides
oxygen as in combustion of carbon
the rest i left out needs a third party element to bond to carbon