When Homing Salmon Navigate Up a River, They

Multiple Choice

When homing salmon navigate up a river, they

A) are influenced as much by habitat quality as by the odor of their birthplace.
B) usually choose correctly at a fork in a stream, but if they choose the wrong branch they are ultimately unable to find their way home.
C) will fail to reach their birthplace if their nasal cavities are plugged.
D) will fail to reach their birthplace if they are blinded.