Keith chens work with animal (monkeys)and money suggests which of the follwing conclusins
1. Animals, specifically monkeys, have some level of understanding of the concept of money and can be trained to use it in exchange for goods or rewards.
2. The use of money may be a learned behavior that is not unique to humans, but can also be observed in other animals, such as monkeys.
3. The ability to understand and use money may be a more widespread phenomenon in the animal kingdom than previously thought, indicating that it may have evolutionary roots.
4. The relationship between animals and money could provide insights into the evolution of economic behaviors in humans and other animals.