Final answer:
Lipids are necessary in a balanced diet because they provide a concentrated source of energy, help in the absorption of fat-soluble vitamins, and are required for the production of hormones and cell functions.
Step-by-step explanation:
Dietary lipids play several essential roles in human health and are a necessary part of a balanced diet for various reasons. The correct answer to why some dietary lipids are a necessary part of a balanced diet among the options provided is b) Lipids provide a concentrated source of energy. Beyond energy storage, lipids are indispensable in the structure and function of cell membranes, they facilitate the absorption of fat-soluble vitamins such as vitamins A, D, E, and K, and are necessary for the production of certain hormones. Additionally, the body requires certain essential fatty acids, like omega-3 and omega-6, which can only be obtained through the diet and are crucial for roles such as reducing inflammation and supporting cell functions.