What can you conclude about fossil by looking at the layers of rock? a. the exact age of the fossil b. the fossils in the lower layers are older than the fossils in the upper layers. c. there is no difference in age between the different layers of rock d. the fossils in the upper layers are the ancestors of the fossils in the lower layers.

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.

What organ is the first to receive nutrients that have been absorbed from the digestive tract?

Examine the air pressure map. which type of line is shown on the map?