In general, Parkinson's disease is caused by the death of dopamine-producing cells in the human brain. University of Washington researchers have experimented with some genetically modified Diptera insect fruit flies, which are growing older Over time, dopamine cells will gradually die. Scientists were surprised to find that when they squeezed tobacco and coffee into juice and fed these fruit flies, the dopamine cells of the fruit flies increased, and the fruit flies became viable again. Therefore, researchers point out that people who have a cigarette addiction and a coffee habit are less likely to develop Parkinson's disease. If the following are true, the above speculations cannot be questioned:. ['There are differences in the mechanism of dopamine cell production in human and Drosophila brains.', 'Of the 4 groups in the experiment, 1 group had the opposite result.', 'Excessive secretion of dopamine cells in the human brain can lead to violent crime.', 'Most diptera insects produce increased dopamine cell division after obtaining new food species.']