Final answer:
The characteristic that defines the members of the kingdom Protista is that they are composed of one or more eukaryotic cells, option C. This diverse group includes single-celled and simple multicellular organisms without specialized tissues.
Step-by-step explanation:
Characteristic of Members of Kingdom Protista
When exploring the characteristics that define members of the kingdom Protista, it's important to recognize that they present eukaryotic cells, meaning they have a nucleus, unlike prokaryotes. Most protists are single-celled organisms, but some can also be multicellular. However, even the multicellular protists lack specialized tissues for nutrient distribution, which is a characteristic feature in the kingdoms of animals and plants. While protists do engage in reproductive mechanisms, they do not solely rely on binary fission for reproduction, as they can reproduce both sexually and asexually, through various complex mechanisms.
Protist diversity is extensive, and members can range significantly in size, habitat, and reproductive strategies. This kingdom includes creatures such as algae, amoebas, and even large multicellular organisms, like kelp. Although some protists can reproduce via binary fission, sexual reproduction via meiosis and fertilization is also common, especially when environmental conditions change or resources become scarce.
The correct option that reflects a characteristic of members of kingdom Protista is C. One or more eukaryotic cells. This is because, by definition, protists are eukaryotic organisms that may be unicellular or multicellular without specialized tissues.