planecie

In a sentence

• Na naszej planecie żyje wiele gatunków zwierząt.

  On our planet, there live many species of animals.

  Here, 'planecie' is the locative case of the noun 'planeta', used after the preposition 'na' to indicate location on the planet.

• Chciałbym podróżować po całej planecie, odkrywając różne kultury.

  I would like to travel across the whole planet, discovering different cultures.

  In this sentence, 'planecie' is also in the locative case, governed by the preposition 'po', which introduces the idea of moving around or across the planet.

• Na naszej planecie ryzyko katastrof ekologicznych jest coraz większe.

  On our planet, the risk of ecological disasters is growing.

  Again, 'planecie' is in the locative case, serving to describe the location where the situation pertains — the planet.