Reading 42 — Read an Academic Passage

Some animals migrate over remarkable distances to reach feeding or breeding areas. Migration is costly because it requires energy and exposes animals to predators and bad weather. Nevertheless, the journey can increase access to seasonal food or suitable nesting sites. Animals use several sources of information to navigate. Some respond to the position of the Sun or stars, while others detect Earth’s magnetic field. Many species also learn landmarks or routes from older individuals. Because navigation may combine several cues, disrupting one cue does not always cause complete disorientation.

Question: Which navigation cue is NOT mentioned?