welches Tier = which animalwelche Tiere = which animals
On the, or by the. Frankfurt am Main translates as Frankfurt (a town) on the (river) Main.
Mean in German: bedeuten, meinen. Mean if a synonym is cruel would be 'gemein'. Just like English the word 'mean' has two meanings. You might 'mean'(intend) to say that someone is a 'mean' (cruel)...
will (from the verb wollen-to want) means he/she/it wants.