Solve this:

Q7. The direction of the water flow in given cells X, Y & Z can be presented as

        (1) X $\to$ Y $\leftarrow$ Z

        (2) ​ X $\to$ Y$\to$ Z

        (3) ​​​ X $\leftarrow$ Y$\leftarrow$ Z

        (4) ​​ X  $\leftarrow$Y$\to$ Z

Dear student,

The correct option is (3) - The movement of water takes place from cell Z to Y and from Y to X :
As the movement of water takes place from lower DPD to higher DPD and it is calculated by the following formula - 
DPD = OP(Ψs)  - TP
So, For cell X, DPD = -30 -10 = -40
For cell Y, DPD = -50 -20 = -70
For cell Z, DPD = -40 - 30 = -70

Although the DPD of cell Y and Z is equal but, the solute potential and turgor pressure of cell Z is higher than that of cell Y. So the movement of water will take place from lower concentration to the higher concentration of solutes.

Regards.