Aprotein channel is a transport protein that a. always moves substances against a concentration gradient. b. pumps ions out of a cell. c. serves as a tunnel for specific substances. d. always requires energy from the cell.

Which of the following is true about the introduction of a non-native species to an environment? (a) they usually adapt quickly so they can have a positive affect on the environment. (b) they can disrupt the environment and cause much damage and devastation to native species. (c) they usually become predators in a food chain and to keep prey populations under control. (d) because the native species are better-adapted to the environment, the non-native species always end up dying out.