Imagine you have an unknown sample that contains one of the four macromolecules. what could you do to determine if the sample contains lipids?
a) mix the sample with water, and observe how it behaves.
b) eat some of it, and observe what happens after digestion.
c) slice the sample, and examine its individual cell structure.
d) burn the sample to see if it contains the element carbon.

C, it's not D and you should never eat something if you don't know what's in it; meaning it's not b, you are talking about macromolecules so you should examine its individual cell structure.

option (a).

Explanation:

Biomolecules are the important organic molecules that plays an important role in the living organism. Four important biomolecules are carbohydrate, proteins, lipids and nucleic acids.

Lipids consist of fatty acids that contain the hydrophobic hydrocarbon tail and the hydrophilic head that contains the carboxylic acids. Lipids can be easily tested by dissolving them in water. Lipids are insoluble in water and starts floating on the surface of water. Lipids are easily soluble in organic solvents. Some lipids may also form micelles in water.

Thus, the correct answer is option (a).