Final answer:
Nail plates are made of keratin, a protein that gives them their hardness and doesn't require oxygen, as they are composed of dead cells filled with keratin.
Step-by-step explanation:
The nail plates are primarily made of keratin, a tough protein that does not require oxygen for its structure or function. This protein is what gives the nails their hardness and resilience. Nail plates are essentially made of dead cells that have been filled with keratin, which is why they do not require a direct blood supply or oxygen. It is important to note that nails grow from the nail matrix, a deep layer of living epidermal tissue, and as they grow, the cells become keratinized and die, forming the rigid nail plate that we see.
Regarding the options given: Collagen and elastin are proteins found in the skin and connective tissues, making them elastic and strong, while melanin is a pigment produced by melanocytes, giving color to the skin, hair, and eyes.
It's also worth noting: the nail bed does not refer to the middle portion of the hard nail plate; rather, it lies beneath the nail plate, providing it support.