Apiece of plastic (sample q), was heated at a constant rate. after 20 minutes of adding heat, the plastic melted. when an identical piece of plastic (sample r), was heated with twice as much heat per minute, the plastic melted in 10 minutes. how do the melting points of the two pieces of plastic compare?
a. the melting point of sample r is double that of sample q.
b. the melting points of sample q and sample r are the same.
c. the melting point of sample r is slightly higher than sample q's.
d. the melting point of sample q is higher than sample r's.

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.