[问答题]
Researchers carried out a similar experime
ymo46 s0a qwm/nt to Louis Pasteur’s f
sg q z/k+zh;gepx92c:amous experiment disproving spon
:;pcexz k+/9sgg zq2htaneous generation, using the set up below at 30°C.
1.Outline the theory of spontaneous generation.
2.1.State two variables that must be controlled in this experiment.
2.2.Explain why it is important to have controlled variables in this study.
3.1.State the letters of three flasks which would show signs of decomposition of broth.
3.2.Explain your answer to part (i).
4.Suggest, with reasons, how the results of the study would differ if the flasks were incubated at 4°C.