Final answer:
The core of eukaryotic cilia and flagella is the axoneme, which contains a 9+2 arrangement of microtubules, essential for their motility.
Step-by-step explanation:
Eukaryotic cilia and flagella are hair-like, motile organelles that project from the surface of a cell. The core of the cilium and flagellum is called the axoneme, which contains a 9+2 arrangement of microtubular structure. In eukaryotic cells, a cilium or flagellum is composed of nine pairs of microtubules, known as doublets, that form a ring around two central microtubules, referred to as the 9+2 array.
This core structure is critical for the movement of these organelles, facilitated by two types of motor proteins, dynein and kinesin, which allow motion along the microtubules. Flagella enable cells such as sperm to move, while cilia can move substances along the cell's outer surface, like in the respiratory tract, where they move mucus toward your nostrils.