Which of the following is a medium of transportation in animal cells?

The question asks specifically about a medium of transportation within animal cells (intracellular transport), not between cells or organs.

The cytoplasm is the gel-like fluid that fills the interior of every animal cell. It serves as the medium through which molecules, ions, organelles, and vesicles are transported from one part of the cell to another. Processes such as cytoplasmic streaming (cyclosis) and vesicular transport all take place within the cytoplasm.

The other options do not fit:

• Blood is a medium of transportation between cells and organs in a multicellular animal, but it is not an intracellular transport medium.
• Latex is a milky fluid found in certain plants (e.g. rubber trees). It is not present in animal cells.
• Cell sap is the fluid found inside the large central vacuole of plant cells. Animal cells typically lack a large central vacuole and do not contain cell sap.

The correct answer is cytoplasm, because it is the internal medium through which materials move within an animal cell.