what molecule remains the same in all fats?

Answer 1

A fat molecule is made up of two components:

1. A glycerol which is the "backbone" of the molecule

2. Fatty acids which are attached to the backbone

Each glycerol binds with three fatty acids molecules and form a triglyceride.

There are several types of fatty acids, and fats are usually made up of a mixture of different types.

Answer 2

Glycerol