As ecological footprints provide an easily communicable way of measuring the ecological bottom‐line condition for sustainability, it is a useful tool for promoting a sustainable future. It is particularly useful for cities, as it is in cities where the battle for sustainability will be won or lost.
1). c ... 2). d ... 3). a ... 4). d ... 5). c ... 6). a
7). b-mass ... c-m/s ... d-Newton's 1st ... e-Newton's 2nd