What are fats also known as?

Fats are also known as lipids. This is because they are composed of fatty acids and glycerol, which are classified as lipids. A is incorrect because while steroids are also classified as lipids, they are a specific type of lipid and do not encompass all fats. C and D are incorrect because proteins and carbohydrates, respectively, are different types of macronutrients and do not fall under the category of fats.