Atmospheric carbon dioxide produces a so-called "greenhouse effect" by trapping heat near earth's surface. what human activities might tend to increase the greenhouse effect?

The widespread, large scale, worlddwide burning of enormous quantities of fossil fuels for their energy, such as coal, oil, and natural gas, could do that, if it ever began and became popular. Oh, wait ! That"s what we've been doing, for a couple of centuries now !

Student 1’s methods would be more accurate, because the student would control more factors. Only one variable at a time (either temperature or acidity) would be tested on each group of worms. On the other hand, Student 2 is testing both factors on all the worms, which could make the results unclear.