You are given four test tubes containing purified biological macromolecules. the test tubes are unlabeled except for a number between 1 and 4. you are told that one test tube contains a protein, one contains a lipid, one contains a carbohydrate, and one contains a nucleic acid. you then perform some tests on the macromolecules and collect the following information:
a. test tubes 2 and 4 contain nitrogen, but the other tubes do not.
b. the contents of test tube 3 are not soluble in water, but the contents of the other test tubes are soluble in water.
c. the contents of test tube 1 can be broken down into subunits that are all exactly identical to each other.
d. the macromolecule in test tube 2 is found to have a globular shape. what are the identities of the macromolecules present in the four test tubes?