There is external and internal so I'll list th external. The most important is skin then mucus, sweat or secretion, hair, nails and tears which are all part of the integumentary. Some internal defenses are white blood cells and T cells.
Either amino acids or genotypes.
Answer:
Flora refers to plant life, while fauna refers to animals!
Explanation:
They have to have a higher density than water to have the ability to stay on the sea floor. Otherwise they would just float to the surface of the water
