19. list the 4 major organic compound groups and briefly describe each group

1. carbs - used by cells to store and release energy also used to make cell structures

2. nucleic acids (DNA) - control the processes of heredity by which cells and organisms reproduce proteins

3. proteins - have many functions, mains are building blocks (structural components of life), enzymes (catalyze chemical reactions), antibodies (act as an immune system), signaling, and transporting

4. lipids - basically just fats

The answer is joseph is observing the colour of the reaction mixture to see whether proteins are present in the given solution.