Final answer:
Steroids have two main functions: being important components of cell membranes and acting as hormone messengers in the body.
Step-by-step explanation:
Steroids have two main biological functions. Some steroids, such as cholesterol, are important components of cell membranes. Many other steroids are hormones, which are chemical messengers that regulate various processes in the body. For example, cortisone is a steroid hormone that is involved in the body's response to stress and inflammation, while sex hormones like estrogen and testosterone regulate sexual development and reproductive processes.