Final answer:
Without organelles, a cell would resemble a fluid-filled sac, as the basic structure is a plasma membrane filled with cytoplasm, lacking defined shapes provided by organelles.
Step-by-step explanation:
Without organelles, a cell would resemble a fluid-filled sac. This is because the basic structure of a cell is a plasma membrane filled with cytoplasm, similar to a plastic bag filled with Jell-O. Without the internal structures such as a nucleus and other organelles, the cell would not have a defined shape provided by these entities' organization and support.
Considering eukaryotic cells, they demonstrate a multitude of shapes that can be influenced by the cytoskeleton and environmental factors, but without organelles, none of these defined shapes can be maintained. Therefore, the answer to the student's question is (b) a fluid-filled sac.