Final answer:
The only human cell that possesses a flagellum, a single, whip-like structure, is a sperm cell, which uses it for swimming towards an egg during fertilization.
Step-by-step explanation:
The only human cell to possess a flagellum, a single, whip-like structure, is a(n) sperm cell. A flagellum is indeed a structure that can be found in eukaryotic cells, like those of humans, as well as in some prokaryotic cells. However, when we are talking about a human cell with a single flagellum, we are referring to a sperm cell.
Sperm are unique among human cells in that they have a flagellum, which is used for propulsion to swim towards an egg during the process of fertilization. This is critical to its role in human reproduction. Other cellular components mentioned in the provided options such as the nucleus, cilia, mitochondrion, and ribosome have different functions and locations within a cell.
For instance, cilia are short, hair-like structures that extend from the plasma membrane and are generally found in large numbers on a cell, functioning to move an entire cell or to move substances along the cell's outer surface.