What is one focus of ecologically sustainable development? 

A)  maximizing the flow of matter and energy resources 
B)  controlling human population size and resource use so that carrying capacity is not exceeded 
C)  eliminating the national debt 
D)  minimizing pollution costs

Ecologically sustainable development focuses on balancing human needs with the capacity of the earth's resources to sustain them. This involves protecting natural resources and ecosystems, as well as reducing waste and pollution. Controlling human population size and resource use is a crucial aspect of achieving ecological sustainability, as it ensures that the carrying capacity of the earth is not exceeded. Maximizing the flow of matter and energy resources may not be sustainable in the long run, as it could result in depletion of natural resources and damage to ecosystems. Eliminating the national debt is a fiscal concern that may not be directly related to ecological sustainability. Minimizing pollution costs is important, but it is only one aspect of a larger goal of sustainable development.