Core
The innermost layer of the hair is the Medulla.
the innermost part of something
The innermost part of a flower is the carpel, which is the female reproductive organ. It consists of the stigma, style, and ovary, where the ovules are located.
The innermost part of something refers to the most central or deepest section. It is the core or nucleus of an object or concept.
The pistil is the innermost whorl of the flower
The innermost part of an object is called its core.
Because it is the innermost part of the planet.
It's called the lower mantle.
Bone marrow.
The core.
There is no layer of Earth that meets that description.
The soft innermost part of a tooth, containing blood vessels and nerves.