Which of the following is not a function of the vacuole?

$1 \, \mu m$ is equal to:

When a living plant cell loses water through osmosis,there is contraction of the contents of the cell away from the cell wall. What is this phenomenon called?

State whether the following statement is true or false:
Plastids are present in both plant and animal cells.

What are the consequences of the following conditions?
$(a)$ $A$ cell containing higher water concentration than the surrounding medium.
$(b)$ $A$ cell having lower water concentration than the surrounding medium.
$(c)$ $A$ cell having equal water concentration to its surrounding medium.

Name the processes by which $CO_{2}$ and $H_{2}O$ move into and out of the cell.