| A | B |
|---|
| competition | this occurs when two or more species must use the same limited resources |
| host | the organism that is harmed by a parasite is called... |
| succession | this is the process of gradual change from one community of organisms to another |
| endangered | once a population drops below a certain number, and the species is not able to recover, the species is called.... |
| hazardous wastes | substances that are very harmful to humans and other organisms |
| extinct | when a species is gone forever |
| parasite | an organism that lives on or in another organism |
| fossils | evidence showing how species have changed as environments change |
