The best explanation for upward city growth is when available land is limited, prompting a trend towards vertical development. Urban areas like New York illustrate this concept, as they build upwards to accommodate more people. Other factors such as waste and resource limitations are secondary reasons for urban development challenges. ;
The upward growth of cities typically occurs when available land is limited, leading to vertical development. This phenomenon is most evident in densely populated urban areas where geographical and infrastructure constraints restrict outward expansion. Option c is the correct choice.
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