Which of the following best characterizes an ecological footprint?

C. A measure of environmental impact.

Explanation:

ecological footprint is an individual's impact on environment.

Measure of Land area best characterises an ecological footprint.

Explanation:

Ecological footprint is the measure of how much land we require and how much we use. It is measured in the global acres and global hectares. The size can change with time, depending upon the population,consumption level, technology and use of resources.  

It is used to take the focus over apparent unsustainability of current practices and inequalities in resource consumption. It Measures the requirement of biologically productive region or area like croplands, forests and fishing grounds but not glaciers, open ocean and  deserts,

as resources become scarce because of population growth, the growth decreases after few years due to lack of resources and food.