A Researcher Is Investigating the Ability of Salmon to Migrate

Multiple Choice

A researcher is investigating the ability of salmon to migrate thousands of miles in the ocean yet return to spawn to the exact location where they were hatched. Data from experiments suggest that more than one type of homing mechanism may be involved in this behavior. When salmon arrive at a river mouth from the open sea, they appear to use olfactory cues to find their home streams, but how do they find their way back to the correct hatching spot along the coastline from the open ocean?
Several experiments were carried out to test the hypothesis that geomagnetic factors (the influence of Earth's magnetic field) play a key role in the ability of salmon to find the correct hatching location along the coast. In one such experiment, salmon hatched in Ketchikan, Alaska were subjected to the geomagnetic characteristics of a different location on the Alaska Peninsula, Cold Bay. The fish were then released to determine to which of the two locations they would return to spawn.
-If the salmon return to spawn at Cold Bay, the behavior involved is primarily ________, but if they return to Ketchikan, the behavior is primarily ________.

A) proximate; ultimate
B) innate; learned
C) learned; innate
D) fixed; altruistic