Pileated Woodpeckers (Dryocopus pileatus) excavate large (>45 cm) cavities in trees that they use for nests and roosts. Wood Ducks (Aix spons) also build nests in suitable tree holes, but cannot excavate their own cavities. Consequently, they frequently use nests of Pileated Woodpeckers. Based on this information, which of the following statements is correct? a. Wood Ducks are ecosystem engineers because they nest in cavities built by woodpeckers. b. Pileated Woodpeckers are ecosystem engineers because they excavate tree cavities that Wood Ducks use to build their nests. c. Pileated Woodpeckers are ecosystem engineers because they excavate tree cavities to build their own nests. d. Neither species is an ecosystem engineer by virtue of their nesting habit.

the answer to this predicament is false, by friend, i had this on a quiz, and i got it wrong, so i learned it, cos i was gonna have it on a test, and i got it right

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."    

d we did this already