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A stable population (constant over time) results when ___. 

Which of the following BEST expresses the concept of population momentum?

The population profile depicted below is based on actual data from a country. Based on the population information contained in the profile, what can you tell about this country?   

Consider a food web.  The three major trophic level components of ecosystems are ___.   

Researchers wanted to determine if pesticide X was effective at killing grasshoppers that typically invade cornfields. Two ten-acre cornfields located 1 mile apart were chosen. The cornfield to the west was sprayed only with water. The cornfield on the east received the same amount of water with a 10% solution of pesticide X. Grasshopper abundance was measured in the fields every week for 10 weeks.  The results were: West field – the number of grasshoppers doubled East field – the number of grasshoppers declined by 50% What was the independent variable in the above experiment?

Deep in the ocean are communities nestled around hydrothermal vents where super-heated water springs from the bottom of the ocean.  No sunlight ever penetrates to these deep regions. The water from the vents is rich in dissolved minerals such as hydrogen sulfide which supports a large population of chemoautotrophic bacteria that use sulfur compounds to form organic matter by chemosynthesis.  These communities frequently have worms, clams, shrimp, and many other organisms clustered together. In hydrothermal vent communities, we would not expect to find ___.

The observation that some usable energy is lost in every energy conversion is explained by the ___. 

Animals that feed on dead organic matter in the soil (such as earthworms, millipedes, and termites) are ___. 

Most developed (affluent) nations are in what phase of the demographic transition?

What is the meaning of this chemical formula?  C6H12O6 + 6O2  6CO2 + 12H2O + energy