Which organelle is found only in plant cells?

Read the following statements and identify the correct option.
$(i)$ Contractile vacuole takes part in osmoregulation and excretion.
$(ii)$ Food vacuole is formed by engulfing the food particles.
$(iii)$ The vacuole is bound by a double membrane called tonoplast.
$(iv)$ Vacuole can occupy up to $90$ percent of the volume of the cell.

In plant cells,the vacuoles can occupy up to .............. of the volume of the cell. (in $\%$)

Given below are some characters of a cell organelle. Identify the correct organelle which shows all the characters described above.
$(i)$ It is a membrane bound space found in the cytoplasm.
$(ii)$ It is bound by a single membrane called tonoplast.
$(iii)$ It contains water,sap,excretory products and other materials not useful to the cell.
$(iv)$ It has higher concentration of sap than the cytoplasm.

The $pH$ of vacuolar cell sap is

The contractile vacuole of an $Amoeba$ placed in salt water will: