The first protists probably appeared around a. 1.5 million years ago b. 170 million years ago c. 1.5 billion years ago d. 5 billion years ago

1.5 billion years ago

Explanation:

Protists are a collection formed up of protozoa, unicellular algae, and fungus forms. We will focus on the being part of this society: the protozoa (proto = first, zoa = beings). Protozoa are the earliest discovered collection of heterotrophic living that utilize and modify complicated meal particles into power. Although protozoans are only made up of a single cell, these organisms control to perform all the necessary responsibilities of life. The protozoa are split into four principal associations: the ciliates, the flagellates, the heliozoans, and the amoebas.

Option (C)

Explanation:

Protists are the kingdom that includes unicellular organisms. These organisms are eukaryotic in nature which means that it has a well-defined nucleus. They may be present in colonies or biofilm. But they re self-sufficient. Since the time of formation of these organisms, they have constantly undergone evolution forming a more complex type of organisms.

The first protists appeared during the proterozoic age at about 1.8-1.5 billion years back.

Hence the most appropriate answer is 1.5 billion years ago i. e option (C)