Which statement best summarizes steroids?

Steroids are defined by their distinctive structure, which consists of four fused carbon rings. This unique arrangement of rings allows steroids to perform a variety of roles in biological systems, including acting as hormones, which are critical for many physiological processes in organisms. The diverse functions of steroids arise from their ability to interact with cell membranes and receptors, influencing signaling pathways and metabolic functions.

The structure of steroids not only determines their functional roles but also differentiates them from other types of biomolecules, such as proteins or carbohydrates. For instance, while glycoproteins are involved in signaling and have complex three-dimensional structures derived from polypeptide chains, steroids do not fall into these categories. Instead, their non-polar nature typically allows them to diffuse through cell membranes and exert effects on target cells directly.