The term 'of the core' can be solved by the word 'nucleic', which is a seven letter word. Nucleic acid is a type of macromolecule that is essential for all known forms of life. It is made up of two components, a sugar-phosphate backbone and nitrogenous bases. The four types of nitrogenous bases are adenine, guanine, cytosine, and thymine. These molecules are responsible for the storage and transmission of genetic information.