GMAT Web TestEngine demo

provide an example of a species that relies on the help of another species in defending itself against a particular predator

provide a point of reference against which the author's description of a related phenomenon can be compared

introduce a phenomenon that casts doubt on experimental results described later in the passage

introduce the phenomenon that the experiment described later in the passage is designed to explain

offer a conventional but probably inaccurate view of how many plants defend themselves from predators