The right answer is Plantae.
Duckweed or water lens, also called lenticules are angiosperm plants that belong to the family Lemnaceae (this family is part of the kingdom Plantae) and in particular to 3 genera: Lemna, Spirodela and Wolffia.
Ducks are present in all continents. When they overgrow, they can be a sign of eutrophication.
Each water lens makes a new leaf that grows, then breaks off and forms a new plant. This vegetative multiplication therefore does not involve seeds or spores.