1. Organelles-. e.g. mitochondria, nucleus.
2. Cells- e.g. epithelial cells, palisade cells.
3. Tissues- e.g. muscles, connective tissue.
4. Organs- e.g. heart, liver.
5. Organ systems- e.g. digestive system, circulatory system
This is because there are many organelles inside a cell and a collection of same cells that creates tissues, a collection of tissues form organs, to carry out a particular function, and a collection of organs working together is an organ system. I think this is what they're after as I had a similar question a little while ago.
