[Campbell Biology P.749] In the periwinkle-crab predation experiment, what were the independ... | Practice Question

In the periwinkle-crab predation experiment, what were the independent variables and the dependent variable?

  • A: Independent variables: Source population of crabs and periwinkles; Dependent variable: Average number of periwinkles killed.
  • B: Independent variable: Shell thickness of periwinkles; Dependent variable: Location of collection.
  • C: Independent variable: Time exposed to predators; Dependent variable: Size of periwinkles.
  • D: Independent variable: Number of male vs. female crabs; Dependent variable: Rate of predation.

Explanation

The researchers set up different treatments based on the source populations northern or southern of both the crabs and the periwinkles. Therefore, the source population of crabs and periwinkles are the independent variables. The outcome measured, the average number of periwinkles killed, is the dependent variable.