You are exploring in the desert and you discover a new unicellular organism. It is small and eukaryotic. Even so, you suspect it is not a protist. Why?

Most protists live in moist habitats.

Explanation:

The protistic or protocist kingdom is a classification of eukaryotic organisms that is composed of mostly unicellular as well as multicellular microorganisms, which, although they do not share many similarities, are grouped into the same kingdom because they do not fit into other. The protista kingdom, also called protoctist, is one of the groups in which biology classifies living beings, more specifically eukaryotes, along with the animal, plant and fungi kingdom. So, protists are all those eukaryotes that cannot be classified as either animals, plants or fungi.

The protista kingdom is a paraphyletic group (they do not contain all the descendants of a common ancestor) and groups together a very diverse set of generally single-celled organisms, both autotrophic and heterotrophic. This variety makes it difficult to characterize them, except for the common features of all eukaryotic beings, that is, possessing cells with a defined cell nucleus.

They depend on humidity to survive, no protistic organism is adapted to live completely on air. So they can not live in the desert. Also, there are not only those that develop in water, but there are also some Protocysts that grow in environments where humidity is very high, requiring the existence of air since many of them carry out the process of Photosynthesis. Through photosynthesis, they absorb the water present in their environment and the nutrients of the support, and through the absorption of Carbon Dioxide they manage to elaborate their own food.