What are flat bones? What are their functions?

Hint: The bones of a flattened person are thin and flat. They have a small curvature on occasion. Flat bones act as a point of attachment for muscles and as a barrier for internal organs.

Complete answer:
The bones of a flattened person are thin and flat. They have a small curvature on occasion. Flat bones act as a point of attachment for muscles and as a barrier for internal organs.
These bones are made up of two thin layers of compact bone with a variable amount of cancellous bone between them, which is where the red bone marrow is found. The majority of red blood cells in an adult are generated in flat bones. The tables of the skull are the layers of compact tissue in the cranial bones; the outer one is thick and durable, while the inner one is thin, dense, and brittle.
The vitreous (glass-like) table is thus named. The diplo is the intervening cancellous tissue that becomes absorbed in the nasal region of the skull, leaving voids filled with air–the paranasal sinuses–between the two tables.
Osteoclasts are typically employed for three reasons: the first is to repair broken bones. They obliterate protruding bone portions or make restoration difficult. They are also employed to collect the calcium that osteoclasts require in order to grow. The form of the bone changes as it grows. The osteoclasts break down the component of the bone that has to be replaced.

Note:
Because flat bones are often thinner than long bones, they only have red bone marrow instead of both red and yellow (yellow bone marrow being made up mostly of fat). The bone marrow fills the space between the osteoblasts in the ring and finally the bony matrix.