The process of absorption can be demarcated into two main phases.
In the first phase, initial rapid uptake of ions into the ‘free space’ or ‘outer space’ of cells – the apoplast, is passive.
In the second phase of uptake, the ions are taken in slowly into the ‘inner space’ – the
symplast of the cells.
In the second phase of ion uptake, the ions are taken in slowly into the ‘inner space’ – the symplast of the cells. Hence, the correct answer is option b.