Cities fall under the category of urban ecosystems. urban ecosystems include nature, humans, and animals in a (mostly) human-built environment. energy flow, nutrient cycles, and resource use are all necessary to maintain an urban ecosystem. most urban ecosystems are heterotrophic because they depend on materials and energy from outside their boundaries.

the significance of this reliance on outside resources is ―

1. variations in a population of moths allow for some of its members to be able to adapt to environmental changes. the better adapted of the moths will be able to survive the change and thus prevail as the “fittest” of the species. (a) describe three mechanisms in which variation can occur within a species population. (b) explain which mechanism or mechanisms would be responsible for the survival of a population of peppered moths better than white moths in an environment affected by industrial soot. justify your answer.

Which of the following can be reduced by the use of renewable energy sources? a. social costs b. economic costs c. environmental costs d. all of the above select the best answer from the choices provided a b c d

Most of the carbon on earth is stored in the form of