Paramecium is a ciliate belonging to the family Paramecidae in the order Hymenostomes. The body of paramecium is small, cylindrical, and composed of only one cell. It is a unicellular animal, hermaphrodite. The most common is Paramecium, with a body length of only 80-300 micrometers. The surface of the body is covered with a membrane, densely covered with many cilia. The paramecium is named after its body shape, which looks like an inverted sole from a flat angle.

Amoeba is a unicellular animal belonging to the genus Amoeba in the family Proteaceae of the order Proteobacteria. There is only a thin plasma membrane on the surface of the body, and the cytoplasm inside the membrane is relatively transparent, which can be clearly distinguished into two parts: endoplasmic and extracellular; Pseudo feet are shaped like fingers, leaves, or needles; Insects can undergo special deformation movements through pseudopodia, which change with the expansion and contraction of pseudopodia; Pseudo foot not only has the function of movement, but also has the function of feeding. After wrapping food, it undergoes intracellular digestion. Named after the constant changes in body shape caused by the movement of the parasite's cytoplasm.

Cyanobacteria, also known as blue-green algae, are a type of large single-cell prokaryotic organism with a long evolutionary history, Gram negative staining, no flagella, containing chlorophyll-a but not chloroplasts (different from eukaryotic algae), and capable of oxygen producing photosynthesis. The difference from photosynthetic bacteria is that photosynthetic bacteria (red snails) undergo more primitive photosynthetic phosphorylation and do not release oxygen during the reaction process, making them anaerobic organisms, while cyanobacteria can carry out photosynthesis and release oxygen.

Chlamydomonas, also known as "unicellular algae". Chlorophyta, Chlamydomonas family. The algal body is a single cell, spherical or oval in shape, with two equally long flagella at the front end, and can swim. There are two flexible vesicles at the base of the flagella; There is also a red eye spot near the front end of the cell. Large cup-shaped color carrier with one starch core. Asexual reproduction produces 2, 4, 8, or 16 motile spores; Sexual reproduction includes homogamy, heterogamy, and ovogenesis. Under unfavorable living conditions, cells stop swimming and undergo multiple divisions, forming a temporary population called an "indeterminate population" with a thick glial sheath on the periphery.