* No specialized organs: They lack the complex systems (like mouths, stomachs, and intestines) that multicellular organisms use to take in and process liquids.
* Direct absorption: They absorb water and nutrients directly across their cell membrane, which is their outer boundary. This process is called diffusion.
* Osmosis: The movement of water across their cell membrane is driven by osmosis, where water moves from areas of high concentration to areas of low concentration.
So, instead of drinking, unicellular organisms rely on the passive movement of water into their cells to maintain their internal environment.
