Volvox

Volvox is a genus of green, spherical single-celled organisms that live in freshwater environments. They form colonies made up of thousands of individual cells working together, often resembling tiny balls or bubbles. Each cell has little hair-like structures called flagella, which coordinate to help the colony swim through water. Some cells handle photosynthesis—producing food using sunlight—while others may specialize in reproduction. This organization makes Volvox an important example of early multicellularity, showing how individual cells can cooperate and differentiate for the benefit of the entire colony.