Astudent wants to study how exposure to water for 24 hours affects bacterial growth
which is an appropriate step of scientific inquiry that the student should complete?
make several guesses about the effects of water on bacterial growth
observe normal bacterial growth for 24 hours,
ask a teacher what he or she thinks about bacterial growth
collect data from other experiments on bacterial growth

Observe normal bacterial growth for 24 hours,

Explanation:

Making guesses are good for hypothesis formulation but the generate a conclusion an experiment should be conducted.

Likewise, asking a teacher can help design an experiment but to be a researcher, the student should conduct the experiment in the lab.

Finally, collecting data from other experiments would not help understand the bacterial growth on specific conditions (water exposure) set for the experiment. Rather, the student should strictly conduct the experiment with the set criteria.

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.