There are 4 unknown samples that you need to identify based on your understanding of this unit. These samples include ________. A nucleic acid, a lipid, an enzyme and an amino acid. Here are the test results: *Nitrogen is present in all test tubes except # 1. *Hydrolysis occurs in all except #2. *Sulfur is absent in all samples except #3. *Phosphate is present in sample #4. WHAT ARE THE CONTENTS OF EACH TEST TUBE? EXPLAIN YOUR REASONING.