Here are some key characteristics of multicellular organisms:

* Specialized cells: Cells in multicellular organisms are often specialized to perform specific functions (e.g., muscle cells for movement, nerve cells for communication).

* Tissues: Similar cells group together to form tissues, like muscle tissue or nervous tissue.

* Organs: Different tissues work together to form organs, like the heart, lungs, or brain.

* Organ systems: Groups of organs collaborate to carry out complex functions, forming organ systems (e.g., circulatory system, digestive system).

Examples of multicellular organisms include:

* Animals: Humans, dogs, birds, fish, insects, etc.

* Plants: Trees, flowers, ferns, mosses, etc.

* Fungi: Mushrooms, molds, yeasts, etc.

* Some algae: Seaweeds, kelp, etc.