Here's why:

* Cytoplasm is the gel-like substance that fills the cell. It's a mixture of water, salts, and various organic molecules.

* Organelles are suspended within the cytoplasm. This means they are surrounded by and held in place by the cytoplasm.

* Cytoplasm provides a medium for transport. It allows for the movement of nutrients, waste products, and other molecules between organelles.

* Cytoplasm provides structural support. It helps to maintain the shape of the cell and provides a framework for organelles to move and function.

While the cytoskeleton, a network of protein filaments within the cytoplasm, plays a crucial role in providing structural support and facilitating movement, it's the cytoplasm itself that forms the foundational medium for all cell organelles.