A team of researchers hypothesizes that some birds use the Earth's magnetic field to navigate during long migrations, in addition to using visual landmarks and the position of the sun.
Which experimental finding, if true, would most strongly support the team's hypothesis?
- A
Some bird species fly thousands of kilometers during migration.
- B
Birds have keen visual systems.
- Ccheck_circle
Migrating birds placed in chambers where the magnetic field could be artificially altered consistently shifted their preferred flight direction to match the new field, even with no visual cues available.
- D
Many birds migrate at night.
Explanation
A directly tests magnetic-field navigation by altering only the field and observing flight-direction changes. B, C, and D are general background.