Parts of our bodies that must be coated with fats to remain healthy

"Why do we need fat?
Virtually all natural foods contain some fat. It is in foods because both plants and animals use fats as the most economical way to store energy. It is needed for their growth, development and function when there is a shortage of food supply (or a shortage of sunlight in the case of plants).

Certain specific dietary fats have other essential functions. We are much like other animals so we do actually need some fat from our diet to survive. And while in general, as with most things, too much fat is bad, a certain amount is perfectly compatible with good health.

What is fat for?
A source of energy – Our body uses the fat we eat, and fats we make from other nutrients in our bodies, to provide the energy for most of our life-functions
Energy store – The extra calories that we consume, but do not need to use immediately, are stored for future use in special fat cells (adipose tissue)
Essential fatty acids – Dietary fats that are essential for growth development and cell functions, but cannot be made by our body’s processes
Proper functioning of nerves and brain- fats are part of myelin- a fatty material which wraps around our nerve cells so that they can send electrical messages. Our brains contain large amounts of essential fats
Maintaining healthy skin and other tissues. All our body cells need to contain some fats as essential parts of cell membranes, controlling what goes in and out of our cells
Transporting fat-soluble vitamins A, D, E and K through the bloodstream to where they are needed
Forming steroid hormones needed to regulate many bodily processes"

The answer would be a