A dog uses its tongue to drink. A robin holds a branch with its feet. A chimpanzee digs for termites with a stick. A worm moves to the top of flooded ground.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which is a learned behavior?
Possibilities:
- A dog uses its tongue to drink.
- A robin holds a branch with its feet.
- A chimpanzee digs for termites with a stick.
- A worm moves to the top of flooded ground.

A chimpanzee digs for termites with a stick.