Final answer:
In North America, states are the most numerous compared to borders and national borders. Each state within the United States has multiple boundaries with others, while there are only two national borders – the United States' borders with Canada and Mexico.
Step-by-step explanation:
When considering what is most numerous in North America - states, borders, or national borders - it is important to consider the context of these terms. In the United States, a state refers to a sub-national entity (e.g., California, Texas) while national borders refer to the geopolitical boundaries that define the country itself. The term border can refer to any division between states or countries, including state borders or national borders.
There are 50 states in the United States, each with its own internal borders. States are numerous because they consist of individual sub-national provinces. Each state can have multiple borders with neighboring states. However, there are only two national borders within North America at the country level – the United States border with Canada to the north and the United States border with Mexico to the south. Therefore, states are the most numerous when compared to individual national borders.