D. Exact ecological footprints are often difficult to calculate, but estimates can be useful in comparing populations.
The ecological footprint refers to the estimation of the productive ecological area used by the human population to meet it's requirement of natural resources like fruits, vegetable, fish, wood, fossil fuel extraction, space used for construction and for other purposes. It is also concerned about the amount of resources used. The exact ecological footprints are often difficult to calculate because of large area being under use of human population and use of resources in the routinely way. The data collection is related with inaccuracies and requires huge financial demand. A rough estimate can be prepared which distinguishes the use of land and other resources at global, country and state level.
