The correct answer is D. Fish stream size preference.
A biological trait is a characteristic of an organism that is passed down from parents to offspring. Ecological traits are biological traits that affect an organism’s interaction with its environment. Some examples of ecological traits include habitat, feeding behavior, and reproductive strategy.
Fish stream size preference is not an ecological trait because it does not affect an organism’s interaction with its environment. Fish stream size preference is a behavioral trait that affects an organism’s choice of habitat.
Habitat is the physical environment in which an organism lives. Feeding behavior is the way an organism obtains food. Reproductive strategy is the way an organism reproduces.
All of these traits affect an organism’s interaction with its environment. Fish stream size preference does not affect an organism’s interaction with its environment, so it is not an ecological trait.