Question

what is one role that ions play within the cell?
turgidity
muscle contraction
dialysis

Explanation:

To determine the role of ions in cells, we analyze each option:

• Turgidity is related to water pressure in plant cells (e.g., due to osmosis of water, not directly ions as a primary role here).
• Muscle contraction relies on ions like calcium ($Ca^{2+}$) for triggering, and sodium/potassium ions for action potentials that initiate contraction.
• Dialysis is a process for filtering blood (not a cellular role of ions). So muscle contraction is a role ions play in cells.

Answer:

B. muscle contraction