Q10

A group of islands are separated from each other by large stretches of water. Each island has its own policy on quarantine. A nearby country is experiencing an outbreak of an infectious disease in its cattle. An investigation is to be designed to find which of the quarantine policies operating on the islands is the most effective. Which of the following would be a suitable design feature of the investigation?
A. The control is the smallest island.
B. The control is the number of infected cattle.
C. The independent variable is quarantine policy.
D. The independent variable is the number of infected cattle.