| A | B |
| Pseudopod | A temporary, foot-like extension of a cell, used for locomotion or engulfing food |
| Nucleus | The region of a eukaryotic cell that contains the cell's main DNA |
| Vacuole | A membrane-bounded "sac" within a cell |
| Ectoplasm | The thin, watery cytoplasm near the plasma membrane of some cells |
| Endoplasm | The dense cytoplasm found in the interior of many cells |
| Flagellate | A protozoan that propels itself with a flagellum |
| Pellicle | A firm, flexible coating outside the plasma membrane |
| Chloroplast | An organelle containing chlorophyll for photosynthesis |
| Chlorophyll | A pigment necessary for photosynthesis |
| Eyespot | A light-sensitive region in certain protozoa |
| Symbiosis | A close relationship between two or more species where at least one benefits |
| Mutualism | A relationship between two or more organisms of different species where all benefit from the association |
| Commensalism | A relationship between two organisms of different species where one benefits and the other is neither harmed nor benefited |
| Parasitism | A relationship between two organisms of different species where one benefits and the other is harmed |
| Cilia | Hairlike projections that extend from the plasma membrane and are used for locomotion |
| Spore | A reproductive cell with a hard, protective coating |
| Plankton | Tiny organisms that float in the water |
| Zooplankton | Tiny floating organisms that are either small animals or protozoa |
| Phytoplankton | Tiny floating photosynthetic organisms, primarily algae |
| Thallus | The body of a plant-like organism that is not divided into leaves, roots, or stems |
| Cellulose | A substance (made of sugars) that is common in the cell walls of many organisms |
| Holdfast | A special structure used by an organism to anchor itself |
| Sessile Colony | A colony that uses holdfasts to anchor itself to an object |