Answer: a, b, d In most tissues, fatty acids are readily oxidized for energy. They are especially important energy sources for the heart, liver and skeletal muscle. In adipose tissue, fatty acids may be re-esterified with glycerol and stored as triglycerides in adipocytes. Stored fat is mobilized during starvation and stress. Hormone-sensitive lipase, present only in adipose tissue, catalyzes the breakdown of stored triglycerides into glycerol and fatty acids. The fatty acids that are produced are released in the circulation. The major lipids in plasma do not circulate in a free form, thus free fatty acids must be bound to albumin. During stress, the activity of hormone-sensitive lipase is increased which leads to mobilization of fat stores. However, fat remains an important fuel source for critically ill patients and as a rule the amount of fat administered to patients receiving total parenteral nutrition should comprise about 5–30% of total nonprotein caloric needs