The overall success of an ecosystem is best judged by the a. health of its producers b. availability of resources c. numbers in each trophies level d. interaction of biotic and abiotic factors (the answer is d.)

Most of the fossils found in virginia are in the coastal plain, valley, ridge, and appalachian plateau regions, best suggesting that these geographic provinces a) were once covered by seawater. b) are the oldest parts of virginia. c) have a great deal of karst topography. d) have large amounts of sedimentary rock.

Which of the following statements about protists are true? a.they are typically found in moist environments. b.they are all unicellular. c.they have a nucleus. d.they are all multicellular.

When a gasoline engine burns gasoline, what type of chemical reaction is occurring?