Fill in the blanks:
1 . In plant cells the vacoules can occupy up to …a… of the volume of the cell.
2 . In the plants , the tomoplast facilitates the transport of a number of ions and other materials …b… concentration gradient into the vacoule, hence their concentration is significantly ...c... in the vacuole than in the cytoplasm.
3 . In Amoeba the ...d... vacuole is important for excertion .
4 . In many cells, as in protists...e... vacuoles are formed by engulfing the food particles.