Final answer:
True, nails are a skin modification similar to animal hooves, consisting mainly of keratin. The nail bed does not refer to the middle portion of the nail plate; it lies underneath.
Step-by-step explanation:
True, the nail is indeed a modification of the skin and is analogous to the hooves of animals. The nail bed refers to the portion of the epidermis, which is the specialized structure at the tips of our fingers and toes.
The nail body, which forms on the nail bed, consists of densely packed dead keratinocytes filled with keratin. The epidermis has evolved to form a specialized structure upon which the nail can continuously grow.
This keratin makes the nails hard yet flexible, serving as a protective cover for our fingertips and toes, enhancing touch sensation and sometimes being used as a tool.
Regarding the statement about the nail bed, it's false that the nail bed refers to the middle portion of the hard nail plate. The nail bed is actually underneath the nail plate and is rich in blood vessels, giving the nail its pink appearance.
The main component of nails is keratin, a strong protein that also constitutes the hair and outer layer of skin. So, the correct answer to which protein nails are mainly made of is C. Keratin.