Answer:
49, where the best fits crosses the x-axis where the mean percentage changes of the mass is 0
Step-by-step explanation:
Water potential may be defined as a measure of the water's free energy in the solution. It is represented by symbol ψ (psi). It is affected by two factors :
-- pressure potential
-- solute
The water potential of pure water is zero.
In the context, the concentration of the NaCl solution that has same water potential as the onions where the line of the best fits crosses x-axis where the mean percentage changes of the mass is zero, that must be equal.