Correct Answer:
A. Zero
In the context of biology and chemistry, the water potential of pure water is defined as Zero. Water potential (Ξ¨) represents the potential energy of water per unit volume relative to pure water in reference conditions. Pure water at standard atmospheric pressure and temperature serves as the fundamental reference point for all other water potential measurements.
- A water potential more than zero is not possible under standard conditions, as pure water is the highest reference.
- A water potential less than zero (negative) is characteristic of solutions, where the presence of solutes lowers the free energy of water.
- Therefore, 'None of these' is incorrect because 'Zero' is the precise and accepted value for pure water.