A bean plant is placed in an experimental chamber and the amount of gases consumed and released is monitored. Predict which of the following gases is produced during periods of darkness.

Aresearcher created three groups based on participants bmi: normal weight, overweight and obese. the hypothesis being tested is that the three groups differ in the mean number of artificially sweetened drinks consumed weekly. which statistical test might the researcher use, assuming a reasonably normal distribution of values.