Define species.

Define stenohaline species.

What are threatened species? Name three categories of threatened species.

Name three categories of threatened species.

Differentiate between: Keystone species and endangered species.

Discuss the concept of endangered species.

Name the association in which one species produces poionous substance or a change in environmental conditions that is harmful to another species.

Discuss the positive interaction between species.

Ecological study of single species is called