The second level of organization in a multicellular organism is tissues.

Here's the breakdown:

1. Cells: The basic, fundamental unit of life.

2. Tissues: Groups of similar cells that work together to perform a specific function. Examples include muscle tissue, nervous tissue, connective tissue, and epithelial tissue.

3. Organs: Structures made up of different tissues that work together for a common purpose. Examples include the heart, lungs, brain, and stomach.

4. Organ Systems: Groups of organs that work together to carry out major bodily functions. Examples include the digestive system, circulatory system, and nervous system.

5. Organism: A complete living being made up of multiple organ systems.

Let me know if you'd like more detail on any of these levels!