The correct answer is A. Locomotion
Step-by-step explanation:
The diatoms are a type of organisms that are unicellular and belong to the algae group, these organisms play an important role in ecosystems by producing oxygen and fertilizing the ocean floor. In term of structure, diatoms are composed of a nucleus because they are eukaryotes, also they contain a cell wall, vacuoles, mitochondria, and other structures in charge of basic functions of the cell. Additionally, most diatoms do not have mobility or locomotion but in some cases, they developed raphe, which is a ridge tissue in the outside of diatoms that work as structures for cell movement of function as part of locomotion.