Continued problem with the use of iuvenis as only masculine. Dictionary listing of this 3rd declension adjective is iuvenis, iuvenis, iuvene meaning young. Iuvenis is also feminine. In this age of gender concerns, could we please translate this when not limited by an adjective to youth or young people as the case is in this sentence?
It is not because they are asking 'how many?'.
Most Latin nouns will use a preposition like in with the ablative to specific location. There are a few nouns however that make use of an older grammatical case that was slowly disappearing called the locative. Only names of cities, towns, small islands (those only big enough to have a single city or town), and a handful of other nouns like domus make use of the locative. We use in here instead of the locative because America is not a city, town, etc.