They feed on a single species, live in a simple environment.
No one tree, even within a single species, has such extraordinary variety.
Typically, though not necessarily, they will be of a single species.
His unique power is the ability to "call" all animals, not just a single species.
"For good solid reasons, the three of us decided to send only a single species."
Although it is usually considered to be a single species, four different forms have been distinguished.
The traditional approach to fisheries science and management has been to focus on a single species.
When I left, not a single intelligent alien species was known.
The two have been classified by some authorities as a single species.
The trees are usually of a single species with clear regional favorites.
