All of the rocks(___) are removed from a desert ecosystem, what would happen to the population of rock dwelling lizards (___) and in turn the animals which eat them?

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.