Study the given below characters of a structure inside a cell and identify the correct one which shows all the characters described.
(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 given characters are related to cell organelle - vacuole. Vacuole is a membrane bound organelle, found in both animal and plant cells but are much larger in plant cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in certain cases they may contain solids which have been engulfed. Vacuoles might store food or any variety of nutrients a cell might need to survive. They can even store waste products so the rest of the cell is protected from contamination.