1. Humans: We are a prime example of multicellular organisms. We are made up of trillions of cells that work together to form tissues, organs, and organ systems.

2. Trees: Trees are also multicellular, with specialized cells forming roots, trunk, branches, and leaves. These cells work in coordination to allow the tree to grow, photosynthesize, and reproduce.

3. Ants: Ants are a fascinating example of multicellular organisms that exhibit complex social structures. They have specialized cells that form different castes within the colony, each with its own role.

Remember that multicellular organisms are defined by having multiple cells that work together in a coordinated fashion.