Here are three different organisms whose cells are enclosed in cell walls:

1. Plants: Plant cells have cell walls made primarily of cellulose, which provides structural support and helps maintain the plant's shape.

2. Bacteria: Bacterial cells have cell walls made of peptidoglycan, a complex molecule that contributes to the cell's shape and protection.

3. Fungi: Fungal cells have cell walls made of chitin, a strong and flexible material that helps the fungi maintain its shape and absorb nutrients.