Final answer:
A tattoo is permanent because the ink is injected into the dermis, which is the second layer of the skin. Therefore, the correct option is 2.
Step-by-step explanation:
A tattoo is permanent because the ink is injected into the dermis, which is the second layer of the skin. The dermis is composed of connective tissue and contains blood vessels, nerves, and sweat glands. When the ink is injected into the dermis, it becomes trapped within the cells and fibers of the connective tissue, making it difficult for the body to remove the ink.
In contrast, if the ink were injected into the epidermis (the outermost layer of the skin), the ink would eventually be shed as the epidermal cells slough off and are replaced. Injecting the ink into the hypodermis (the subcutaneous layer) would result in the ink being too deep and not visible on the surface of the skin.