Which protist group exhibits mitochondrial remnants with reduced functionality?
a. slime molds
b. diatoms
c. parabasalids
d. dinoflagellates

The diverse collection of organisms, which do not fit into the plant, animal, fungi, or bacterial groups is known asprotists. They are mainly microscopic and are formed of a single cell, that is, unicellular. They are eukaryotes as they exhibit a nucleus and other membrane-bound organelles.

Slime molds refer to the group of amoebozoans, which are identical to fungi morphologically.

Diatoms refer to the protists, which are photosynthetic and unicellular. They are enclosed in acell wall and are formed of silicon dioxide found in the matrix of organic molecules.

Dinoflagellates are morphologically diverse, they can be heterotrophic, mixotrophic, or photosynthetic.

The slime molds, dinoflagellates, and diatoms do not possess the remnants of mitochondria with diminished functionality.

Thus, the options a, b, and d are incorrect.

In the kingdom Protista, parabasalids come under the subgroup Excavata. They possessmitochondria with diminished functionality, these are known as hydrogenosomes. They are named so as they work anaerobically during which hydrogen gas is generated as a by-product.

Hence, the correct answer isoption c.