You'll want to use ‘die Katze’ to mention ‘the cat’ within the nominative or accusative instances. ‘Der Katze’ implies the dative or genitive case. Why do Individuals say 'Gesundheit' instead of 'Bless you' when anyone sneezes? I are aware that the two phrases are employed and also the phrase 'gesundheit' https://magazinerde.de/haufige-verhaltensprobleme-und-losungen-bei-katzen/