Ecologists often say that one individual living in a developed country cannot be counted as ecologically equal to one individual from a developing country because:

The answer is because "the use of natural resources per person is different."

Explanation:

Everything we use these days are based on natural resources and every person uses these resources according to their need. Natural resources can be renewable or non-renewable. Some examples of natural resources which are found on earth includes soil, air, water etc. and we cannot live on this earth without these natural resources.