Solution: The absorption process can be divided into two distinct phases. The first phase involves a passive uptake of ions into the apoplast, which is the cell’s “free space” or “outside space.” The ions are gently absorbed into the cells’ symplast -‘inner space’ – in the second phase of uptake. Ion-channels, transmembrane proteins that act as selective pores, are usually responsible for the passive transport of ions into the apoplast. The active process of ions entering and exiting the symplast necessitates the expenditure of metabolic energy. The movement of ions is commonly referred to as flux; inward movement into cells is referred to as influx, while outward movement is referred to as outflow.