The portion of living skin that supports the nail plate is the:

The portion of living skin that supports the nail plate is indeed the nail bed. The nail bed is the part of the finger or toe under the nail plate and is made of soft tissue that provides a stable base for the nail. It contains blood vessels and nerves, which contribute to the overall health and growth of the nail. The nail bed plays a crucial role in the attachment of the nail plate, ensuring it stays securely in place while allowing for some flexibility during everyday activities.

In contrast, the nail root is the hidden part of the nail that lies beneath the fold of the skin at the base of the nail. The nail matrix, which is located under the nail root, is where the actual growth of the nail occurs, producing new cells that contribute to the formation of the nail plate as it grows outwards. The nail groove, on the other hand, refers to the channels on either side of the nail that facilitate its growth but does not provide support. Each of these components serves a distinct function in the overall structure and health of the nail, but it is the nail bed that is specifically recognized for supporting the nail plate.