What is a function of fats in biological systems?

Fats play multiple crucial roles in biological systems, which is why the choice indicating that all listed functions are applicable is the correct answer.

Fats primarily serve as a vital source of energy, being more energy-dense than carbohydrates or proteins. In particular, they are stored in adipose tissue and can be mobilized when energy is required, making them essential for maintaining energy balance in living organisms.

Additionally, fats are involved in the production of hormones. Certain types of fats, such as cholesterol, are precursors to steroid hormones, which play significant roles in regulating various physiological processes, including metabolism, immune response, and reproductive functions.

Furthermore, fats act as lubricants in the body. They help to create a smooth surface in areas such as joints and facilitate the movement of organs, contributing to overall bodily function and comfort.

Therefore, the comprehensive nature of fat's functions in providing energy, producing hormones, and acting as a lubricant reinforces the correctness of the answer that encompasses all these essential roles.