A scientist grew Chlorella, a single-celled photosynthetic algae, for 3 weeks in a laboratory culture. The culture medium contained dissolved carbon dioxide and other nutrients. At the beginning and end of the 3-week period, the scientist measured the rate of synthesis for certain biological molecules. The results are shown in the following graph. The y axis of the bar graph is labeled milligrams per liter per minute and is marked at increments of 0,2,4,6,8,10, and 12. The x axis is labeled Biological molecules and there are 4 different groups on the x axis labeled proteins, nucleic acids, lipids, and carbohydrates. There are 2 bars per group, one bar is labeled beginning and the other bar is labeled end. For proteins, the beginning and end bars are both at 6 on the y axis. For nucleic acids, the beginning bar is at 4 on the y axis and the end bar is at 2 on the y axis. For lipids the beginning bar is at 4 on the y axis and the end bar is at 2 on the y axis, and for carbohydrates both the beginning bar and th