When using a microscope to view cells you obtained from scraping under your fingernails, you notice that the cells lack nuclei; therefore, you conclude that the cells must be a type of cell.

Bacteria

Explanation:

There are two kinds of cells found in/on the human body that lacks nucleus

Since the material observed under the microscope was scraped from under the finger nails and there was no indication of broken skin, it is likely that the observed cells are bacteria.

materials water oxygen those are the things i can think of in this moment.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.