The watery substance that fills the interior of cells and suspends organelles is called cytoplasm.

Here's a breakdown:

* Cytoplasm is a gel-like substance that fills the space between the cell membrane and the nucleus.

* It's primarily composed of water, but it also contains dissolved salts, sugars, proteins, and other molecules.

* The cytoplasm is where many of the cell's metabolic processes take place, and it provides a medium for the movement of organelles and other cellular components.

* It also helps to maintain the cell's shape and structure.

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