Answer:
The dirt, seawater, and the plants all comprise various substances, therefore, making them a mixture of substances. The dirt is generally an amalgamation of various kinds of rocks and soil, the rocks and soils exhibit distinct compositions, comprising anything from life and dead matter.
The seawater majorly comprises salt and water, therefore, making it a mixture of some of the constituents. The plants exhibit all the kinds of chemicals in them, one of the most prevailing is the water, they are also considered as the natural storehouse of carbon, along with these the plants also possess various other components, therefore, making them a mixture of components.