Final answer:
Cholesterol is the fat-related substance produced by the liver and obtained through animal-based foods that is the structural basis for all steroid hormones and Vitamin D. It is also involved in fat absorption and important for the proper functioning of the body.
Step-by-step explanation:
The fat-related substance produced by the liver and obtained through animal-based foods that serves as the structural basis for all steroid hormones and Vitamin D is cholesterol. Cholesterol is mainly synthesized in the liver and is the precursor for steroid hormones like testosterone and estradiol, as well as Vitamin D. It is also involved in the emulsification of fats and is a key component of the plasma membrane of animal cells.