Water Pollution Answers

Why has the spread of the herbicide-resistant hydrilla through Florida’s waterways resulted in them no longer being navigable by most boats?a.Thy hydrilla has induced a drought that drained the waterways.b.The weed clogs propellers that boats use for propulsion.c.The sticky leaves of the weed hold boats in place.d.All of the above

Which of the following is an example of mechanical control of nonnative species?a.pesticidesb.herbicidesc.net barriersd.inspections

Which of the following is not true concerning the zebra mussel in the United States?a.It was introduced accidentally.b.It was first introduced in the Great Lakes.c.It is still spreading throughout the United States.d.It can be eliminated from a river with minimal effort.

Which of the following is true concerning hull fouling from commercial shipping and recreational boating?a.It constitutes less than half of all nonnative species introductions.b.The revenue brought in from these industries is relatively small.c.It is difficult to prevent since ship hulls begin, conduct, and end voyages in water.d.It is best combated by chemical treatments.

Nonnative species are only introduced unintentionally.

Invasive species often unbalance the ecosystems into which they are introduced because _______.a.they did not co-evolve with the natural species and lack natural controls, like predatorsb.they breed quickly and have the potential to overpopulate an areac.they consume local resourcesd.none of the above

Introducing invasive species to an ecosystem results in an increase in biodiversity.

The rusty crayfish is harmful to native species of crayfish because it clear cuts the bottom of waterways leaving native species without a food supply.

Which of the following is not true about nonnative species?a.They can have positive impacts on an ecosystem.b.They can have negative impacts on an ecosystem.c.They can be introduced within their natural range.d.A nonnative species can be an invasive species.

Ships that use ballast water are not in danger of introducing invasive species into aquatic habitats.