Diatoms (Division Bacillariophyceae) are one of the seven groups of phytoplankton, unicellular organisms that are photosynthetic.
(Diatoms; are; one of the seven groups of phytoplankton) (unicellular organisms; are; photosynthetic)
Diatoms unicellular organisms
are are
one of the seven groups of phytoplankton
photosynthetic