1. Based on the given information, your answer for the problem is correct. The problem is to investigate the effect of light on the growth of Spanish needle seeds.
2. Your hypothesis is partially correct. However, the hypothesis should be more specific and include the comparison of different colors of light. Here's an improved hypothesis: "If the Spanish needle seeds are exposed to different colors of light, including sunlight, red light, and green light, then the growth of the seeds will be the greatest in sunlight compared to red and green light."
3. Your answer for the independent variable is correct. The independent variable in this experiment is the different colors of light used to grow the Spanish needle seeds.
4. Your answer for the dependent variable is correct. The dependent variable in this experiment is the growth of the Spanish needle seeds, measured in centimeters.
5. Your control group is incorrect. The control group should be the group that receives the "normal" treatment, which in this case is normal sunlight. Therefore, the control group is the tray of Spanish needle seeds exposed to sunlight.
6. Your answer for the constants is correct. The constants in this experiment include the exposure of light to the Spanish needle seeds, the amount of water given, and the type of soil provided to all the trays.
To construct a graph for problem 7, you can use a line graph. The x-axis should represent the different days (1, 2, 3, etc.), and the y-axis should represent the growth of the Spanish needle seeds in centimeters. Each line on the graph should represent a different treatment (sunlight, red light, and green light). Then, plot the data points from table 1 on the graph and connect them with lines to show the growth of the Spanish needle seeds over time for each treatment.