After the first 15 minutes, describe the cross-section of the thin celery slice. What does it look like? Try to identify the stringy transport bundles of xylem and phloem. What color are they? How does this lab prove vascular tissues carry water and minerals up the stem? After 24 hours, look carefully at the leaves of the celery. What color are they? Explain the change in color of the leaves that you saw.

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.