Many migratory birds navigate using a combination of cues — the Sun's position, star patterns, magnetic fields, and learned landmarks. Disrupting any one cue typically does not stop the journey; the birds compensate by relying more heavily on the others. This redundancy, biologists argue, is what makes long-distance migration robust enough to be evolutionarily viable.
Which choice best states the main idea of the text?
- Acheck_circle
The redundancy of multiple navigation cues is what makes bird migration robust.
- B
Migratory birds rely on a single navigation cue.
- C
Magnetic fields are the most important cue.
- D
Long-distance migration is rare.
Explanation
The passage centers on redundancy as the key to robust migration — B. A contradicts; C and D are unsupported.