Which of the following organs is NOT cushioned by fats in the body?

The skin is not an organ that is cushioned by fat in the same way that the heart, liver, and brain are. While skin does contain some layers of fat through the subcutaneous tissue (the layer of fat just beneath the skin), it does not rely on fat to the same extent as these other organs for protection and cushioning.

The heart is surrounded by a layer of fat known as epicardial fat, which provides cushioning as well as insulation. The liver, although not primarily cushioned by fat, is also protected by surrounding fat in the abdominal cavity. The brain is encased in cerebrospinal fluid (CSF) and surrounded by a layer of fat in the skull, allowing it to have protection from impact and movement.

In contrast, the primary function of the skin is to act as a barrier for protection against external factors, rather than relying on fat for cushioned support like the internal organs do. Thus, it is correct that the skin is not classified as an organ that is cushioned by fat in the same significant manner as the others listed.