Questions & Answers about Przed domem jest drzewo.
After the preposition przed (when it indicates location), Polish requires the instrumental case. The base noun dom (house) becomes domem in the instrumental.
• Nominative (subject): dom
• Instrumental (with przed): domem
We use jest (3rd person singular of być) because we’re talking about one tree:
• One tree → Przed domem jest drzewo.
• More trees → Przed domem są drzewa. (you’d switch to plural są)