This is an organic substance made of the elements c,h, and o; it is usually found in long chains in lipids; a glycerol and three of these form a fat or lipid. what is the substance?

The answer is Fatty acids.

The correct answer for this question is that a statement that can be proven by observation or measurement is known as a fact. The other possible answers here simply refer to idea that different individuals can place value on, but that are not necessarily known to be true.