During a practical lesson, a student notes the following features of some organisms: ‘They are round, unicellular organisms that can be seen using a light microscope. Their diameter is $0.01\,\text{mm}$. Cytoplasm is present and, after staining, a nucleus can be observed. There is a vacuole.’ What is being described?
- Abacterium
- Bfungus
- Cplant
- Dvirus