The important paper by Hahn and Weinberg extended the early studies from their lab and others in which mouse 3T3 cells were found to be transformed by single oncogenes (like mutant ras). What was the key difference in their experimental system that led them to conclude that at least 3 changes (expression of telomerase, presence of an oncogene like mutant ras, and decreased function of p53/Rb via SV40 Large T antigen) were required to transform non-immortalized cells

'which of these statements about the scientific method is not true? all experiments must follow the same number of steps in the procedure. experiments may be repeated several times. some unexpected results can be beneficial. experimental results may or may not support the hypothesis.

What is usually (but not always) related to the metabolic processes of living organisms in its organic form?

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.