laughing at something funny. dogs doing tricks when told. doing your homework at the same time each day. salmon returning to their birthplace to lay their eggs.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: An example of an instinct is
Possibilities:
- laughing at something funny.
- dogs doing tricks when told.
- doing your homework at the same time each day.
- salmon returning to their birthplace to lay their eggs.

salmon returning to their birthplace to lay their eggs.